Re: "#!/usr/bin/env python" vs. "#!/usr/bin/python"?
On 28/09/12 12:57, Roy Smith wrote: > But, you might as well get into the habit of > using the /usr/bin/env flavor because it's more flexible. In the same manner as one's freedom-fighter is another's fundamentalist terrorist, what's flexible could be also dangerous. E.g., #!/usr/bin/env python is forbidden in the core Fedora packages (https://fedoraproject.org/wiki/Features/SystemPythonExecutablesUseSystemPython), because nobody is willing to risk that by some random python binary in /usr/local/bin some core infrastructure of Fedora installations (e.g., yum) could be broken. Matěj -- http://mail.python.org/mailman/listinfo/python-list
Re: "#!/usr/bin/env python" vs. "#!/usr/bin/python"?
On 12-09-28 06:19 AM, D'Arcy Cain wrote: Not just flexible but portable. On various systems I have Python in /usr/bin, /usr/local/bin and /usr/pkg/bin. "#!/usr/bin/env python" finds it in each case so I only need one version of the script. +1. This also resolves correctly on Cygwin, even if Python is installed via Windows installers (as long as it's on system PATH). Tremendously useful if you're bouncing between *nix and Windows regularly. -- Demian Brecht @demianbrecht http://demianbrecht.github.com -- http://mail.python.org/mailman/listinfo/python-list
Re: "#!/usr/bin/env python" vs. "#!/usr/bin/python"?
On Fri, 28 Sep 2012 09:19:54 -0400, D'Arcy Cain wrote: >Not just flexible but portable. On various systems I have Python >in /usr/bin, /usr/local/bin and /usr/pkg/bin. "#!/usr/bin/env python" >finds it in each case so I only need one version of the script. Good to know. -- http://mail.python.org/mailman/listinfo/python-list
Re: "#!/usr/bin/env python" vs. "#!/usr/bin/python"?
On Fri, 28 Sep 2012 06:57:28 -0400 Roy Smith wrote: > > I've seen both shebang lines to run a Python script on a *nix host: > > > > #!/usr/bin/env python > > #!/usr/bin/python > > > > What's the difference? > > The first one looks through your PATH to find the right python > interpreter to run. The second one is hard-wired to run /usr/bin/python. > > If you only have a single copy of python installed, it doesn't really > matter which you use. But, you might as well get into the habit of > using the /usr/bin/env flavor because it's more flexible. Not just flexible but portable. On various systems I have Python in /usr/bin, /usr/local/bin and /usr/pkg/bin. "#!/usr/bin/env python" finds it in each case so I only need one version of the script. -- D'Arcy J.M. Cain | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. IM: da...@vex.net -- http://mail.python.org/mailman/listinfo/python-list
Re: "#!/usr/bin/env python" vs. "#!/usr/bin/python"?
On Fri, 28 Sep 2012 06:57:28 -0400, Roy Smith wrote: >The first one looks through your PATH to find the right python >interpreter to run. The second one is hard-wired to run /usr/bin/python. > >If you only have a single copy of python installed, it doesn't really >matter which you use. But, you might as well get into the habit of >using the /usr/bin/env flavor because it's more flexible. Thanks guys. I suspected that's what the difference was. -- http://mail.python.org/mailman/listinfo/python-list
Re: "#!/usr/bin/env python" vs. "#!/usr/bin/python"?
In article <34va6856ocuas7jpueujscf3kdt7k44...@4ax.com>, Gilles wrote: > Hello > > I've seen both shebang lines to run a Python script on a *nix host: > > #!/usr/bin/env python > #!/usr/bin/python > > What's the difference? The first one looks through your PATH to find the right python interpreter to run. The second one is hard-wired to run /usr/bin/python. If you only have a single copy of python installed, it doesn't really matter which you use. But, you might as well get into the habit of using the /usr/bin/env flavor because it's more flexible. I'm working on a number of different python projects. For each one, I set up a new virtual environment using virtualenv. This lets me run different versions of python in different projects, with different collections of installed packages (and possibly different versions). I can only do this because I use the /usr/bin/env line in all my scripts. -- http://mail.python.org/mailman/listinfo/python-list
Re: "#!/usr/bin/env python" vs. "#!/usr/bin/python"?
Gilles writes: > #!/usr/bin/env python > #!/usr/bin/python > > What's the difference? Not much if your python is /usr/bin/python: env looks for python and finds the same executable. When python is not /usr/bin/python but something else that is still found by your system, /usr/bin/env still finds it. For example, in a server where I work, python3 is installed as something like /opt/python/3.2.2-gcc/bin/python3. There is no /usr/bin/python3 at all, but "#! /usr/bin/env python3" works. -- http://mail.python.org/mailman/listinfo/python-list
"#!/usr/bin/env python" vs. "#!/usr/bin/python"?
Hello I've seen both shebang lines to run a Python script on a *nix host: #!/usr/bin/env python #!/usr/bin/python What's the difference? Thank you. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Brian Vanderburg II <[EMAIL PROTECTED]> wrote:
>D'Arcy J.M. Cain wrote:
>> Brian Vanderburg II <[EMAIL PROTECTED]> wrote:
>>
>>> This is sort of related, but I'm wondering what is different between
>>> "#!/usr/bin/env python" and "#!python". Wouldn't the second do the same
>>> thing, since an absolute path is not specified, find 'python' from the
>>> PATH environment, I don't really know.
>>
>> Well, I know what happened when I tried it. What happened when you
>> tried it?
>
>I haven't tried it but I've seen some files like written that in the
>past with just a name and no path for some other interpreter (perl or sh
>probably) and didn't know what the different was or if it was even
>valid.
It's not valid. The shebang line (#!) must specify a full path. When you
saw the lone word ("perl"), it was probably a /usr/bin/env line, just we
have been discussing.
>I at a windows system now so I can't try it yet.
*IF* you are interested in playing with Linux, most of the distributions
have bootable CDs that will bring up a full Linux environment without ever
touching your hard disk.
--
Tim Roberts, [EMAIL PROTECTED]
Providenza & Boekelheide, Inc.
--
http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
D'Arcy J.M. Cain wrote: On Thu, 08 May 2008 07:31:17 -0400 Brian Vanderburg II <[EMAIL PROTECTED]> wrote: This is sort of related, but I'm wondering what is different between "#!/usr/bin/env python" and "#!python". Wouldn't the second do the same thing, since an absolute path is not specified, find 'python' from the PATH environment, I don't really know. Well, I know what happened when I tried it. What happened when you tried it? I haven't tried it but I've seen some files like written that in the past with just a name and no path for some other interpreter (perl or sh probably) and didn't know what the different was or if it was even valid. I at a windows system now so I can't try it yet. Brian Vanderburg II -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On Thu, 08 May 2008 07:31:17 -0400 Brian Vanderburg II <[EMAIL PROTECTED]> wrote: > This is sort of related, but I'm wondering what is different between > "#!/usr/bin/env python" and "#!python". Wouldn't the second do the same > thing, since an absolute path is not specified, find 'python' from the > PATH environment, I don't really know. Well, I know what happened when I tried it. What happened when you tried it? -- D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
For me, the difference is #!python doesn't work for me. I get a bad interpreter error. On Thu, May 8, 2008 at 6:31 AM, Brian Vanderburg II < [EMAIL PROTECTED]> wrote: > This is sort of related, but I'm wondering what is different between > "#!/usr/bin/env python" and "#!python". Wouldn't the second do the same > thing, since an absolute path is not specified, find 'python' from the PATH > environment, I don't really know. > > Brian Vanderburg II > > -- > http://mail.python.org/mailman/listinfo/python-list > -- | _ | * | _ | | _ | _ | * | | * | * | * | -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
This is sort of related, but I'm wondering what is different between "#!/usr/bin/env python" and "#!python". Wouldn't the second do the same thing, since an absolute path is not specified, find 'python' from the PATH environment, I don't really know. Brian Vanderburg II -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On May 6, 9:06 pm, Ben Finney <[EMAIL PROTECTED]> wrote: > "Wojciech Walczak" <[EMAIL PROTECTED]> writes: > > 2008/5/6, Banibrata Dutta <[EMAIL PROTECTED]>: > > > > Use /usr/bin/env. If env is not in /usr/bin, put a link to it there. > > > > So why not put symlink to Python over there on all machines, if > > > we can put one (or env itself) there ? > > > To avoid linking all the rest of interpreters like perl, ruby, lua > > and dozens of others. > > The argument was being made from "thousands of scripts". Isn't "dozens > of symlinks" better? > It depends on single user vs multi user. We keep multiple versions of packages because some software requires the older versions. Which version do we symlink to? What if we simultaneously require access to two different versions? For example, to keep legacy software going, or to test updated versions while keeping operational versions running. What if we have shared file systems, and we have multiplatform versions? Python for solaris, python for tru64? In a sense, we do have dozens of "virtual" links, using the modules package to adjust paths on the fly. This is more flexible than having a static symlink in /usr/bin. It allows us to select on a per user, per process, per script basis, the python we want, version, platform etc. With a static symlink, every user/process/job gets the same python, unless you want to flip symlinks around. Also, every 10 years or so, each platform gets replaced, so we are replacing platforms here every few years. And we don't always get the same replacement system. Sure we can go in and touch up all the scripts. But it just seems so much easier and flexible to tell a python/bash/other script to use what you get from the path, and set the paths. Of course, things are different on a single user desktop system, with its own filesystems. If you are sure where python is, and you only have one python, and you don't mind revisiting your scripts and editing them if things change, by all means hard code the python path in. A -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Banibrata Dutta wrote: On 5/6/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: At our site we run IRIX, UNICOS, Solaris, Tru64, Linux, cygwin and other unixy OSes. We have python installed in a number of different places: /bin/python /usr/local/bin/python /usr/bin/python /opt/freeware/Python/Python-2.5.1/bin/python ~mataap/platform/python/python-2.5.1 So I cannot assume a single location for python. Nor for any other tool, really. Bash for example. It may indeed be in /usr/bin on many systems, on many others it is not. Note the version specific install points. This allows us to switch over easily to different versions, and keep older versions in case they are needed. We can test new versions before cutting over to them operationally. (This matters for tools that are still changing, like python or bash.) We use the very handy 'modules' package (not python modules, not fortran modules) to adjust our paths and environment variables as needed. Some of the install points are determined by policy, or historical constraints, or hardware limits, or file system layout. Now it is true that it is easy to edit a single script to change the hashbang line. It is not easy to change several hundred scripts, on different machines. It is easy to adjust the environment to point to the right python path, and have all your scripts pick it up automatically. Looks reasonable thing to do... Use /usr/bin/env. If env is not in /usr/bin, put a link to it there. So why not put symlink to Python over there on all machines, if we can put one (or env itself) there ? A symlink directly to python (or whatever) would not help when testing version x.y.z, while still leaving version a.b.c in place for the other tools/scripts/programs to keep using. -- Ethan -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
2008/5/6, Ben Finney <[EMAIL PROTECTED]>: > > > So why not put symlink to Python over there on all machines, if > > > we can put one (or env itself) there ? > > To avoid linking all the rest of interpreters like perl, ruby, lua > > and dozens of others. > The argument was being made from "thousands of scripts". Isn't "dozens > of symlinks" better? I think that depending on /usr/bin/env is more farsighted and saves some future headaches. Creating links in /usr/bin/ means, that you have to change them whenever you update your software (e.g. any of your many interpreters ;-)). Changing the "#!/usr/bin/python" into "#!/usr/bin/env python" means that you do your job once, and you can sleep well. It also is more portable. How was it in perl? perl -p -i -e 's/#\!\/usr\/bin\/python/#\!\/usr\/bin\/env python/' *.py Funny thing, I have just ls'ed /usr/bin/python on my system: $ ls -l /usr/bin/python lrwxrwxrwx 1 root root 24 2007-11-16 14:02 /usr/bin/python -> /usr/local/bin/python2.5 :-) -- Regards, Wojtek Walczak http://www.stud.umk.pl/~wojtekwa/ -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
"Wojciech Walczak" <[EMAIL PROTECTED]> writes: > 2008/5/6, Banibrata Dutta <[EMAIL PROTECTED]>: > > > Use /usr/bin/env. If env is not in /usr/bin, put a link to it there. > > > > So why not put symlink to Python over there on all machines, if > > we can put one (or env itself) there ? > > To avoid linking all the rest of interpreters like perl, ruby, lua > and dozens of others. The argument was being made from "thousands of scripts". Isn't "dozens of symlinks" better? -- \ "It is difficult to get a man to understand something when his | `\ salary depends upon his not understanding it." —Upton | _o__) Sinclair, 1935 | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
2008/5/6, Banibrata Dutta <[EMAIL PROTECTED]>: > > Use /usr/bin/env. If env is not in /usr/bin, put a link to it there. > > So why not put symlink to Python over there on all machines, if we can > put one (or env itself) there ? To avoid linking all the rest of interpreters like perl, ruby, lua and dozens of others. -- Regards, Wojtek Walczak http://www.stud.umk.pl/~wojtekwa/ -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On 5/6/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > At our site we run IRIX, UNICOS, Solaris, Tru64, Linux, cygwin and > other unixy OSes. > > We have python installed in a number of different places: > /bin/python > /usr/local/bin/python > /usr/bin/python > /opt/freeware/Python/Python-2.5.1/bin/python > ~mataap/platform/python/python-2.5.1 > > So I cannot assume a single location for python. Nor for any other > tool, really. Bash for example. It may indeed be in /usr/bin on many > systems, on many others it is not. > > Note the version specific install points. This allows us to switch > over easily to different versions, and keep older versions in case > they are needed. We can test new versions before cutting over to them > operationally. (This matters for tools that are still changing, like > python or bash.) > > We use the very handy 'modules' package (not python modules, not > fortran modules) to adjust our paths and environment variables as > needed. > > Some of the install points are determined by policy, or historical > constraints, or hardware limits, or file system layout. > > Now it is true that it is easy to edit a single script to change the > hashbang line. It is not easy to change several hundred scripts, on > different machines. It is easy to adjust the environment to point to > the right python path, and have all your scripts pick it up > automatically. Looks reasonable thing to do... > > Use /usr/bin/env. If env is not in /usr/bin, put a link to it there. So why not put symlink to Python over there on all machines, if we can put one (or env itself) there ? -- regards, Banibrata http://www.linkedin.com/in/bdutta -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
At our site we run IRIX, UNICOS, Solaris, Tru64, Linux, cygwin and other unixy OSes. We have python installed in a number of different places: /bin/python /usr/local/bin/python /usr/bin/python /opt/freeware/Python/Python-2.5.1/bin/python ~mataap/platform/python/python-2.5.1 So I cannot assume a single location for python. Nor for any other tool, really. Bash for example. It may indeed be in /usr/bin on many systems, on many others it is not. Note the version specific install points. This allows us to switch over easily to different versions, and keep older versions in case they are needed. We can test new versions before cutting over to them operationally. (This matters for tools that are still changing, like python or bash.) We use the very handy 'modules' package (not python modules, not fortran modules) to adjust our paths and environment variables as needed. Some of the install points are determined by policy, or historical constraints, or hardware limits, or file system layout. Now it is true that it is easy to edit a single script to change the hashbang line. It is not easy to change several hundred scripts, on different machines. It is easy to adjust the environment to point to the right python path, and have all your scripts pick it up automatically. Use /usr/bin/env. If env is not in /usr/bin, put a link to it there. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
In article <[EMAIL PROTECTED]>, Gabriel Genellina <[EMAIL PROTECTED]> wrote: > >I can't believe some angry responses in this thread - it's just a >technical question, not about which is the best team in the [preferred >sports here] National Championship... http://www.netfunny.com/rhf/jokes/91q3/usolym.html -- Aahz ([EMAIL PROTECTED]) <*> http://www.pythoncraft.com/ Help a hearing-impaired person: http://rule6.info/hearing.html -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
I work on an AIX system where /usr/bin and /usr/local/bin apps can only be installed by root. Our system doesn't have python or many other tools we like to use installed so we have to install python in an alternate directory location. We have a system installation of Perl installed, but it's a release or two older than what we need, so we have done the same for perl. Thus, #!/usr/bin/env whatever allows our developers to experiment without always requiring the services of the admins, who are spread too thinly amongst all the other *Nixes they have to support, and who are also separated by many layers of red tape from us. On Sat, May 3, 2008 at 10:24 AM, Lou Pecora <[EMAIL PROTECTED]> wrote: > In article <[EMAIL PROTECTED]>, > Grant Edwards <[EMAIL PROTECTED]> wrote: > > > On 2008-05-02, D'Arcy J.M. Cain <[EMAIL PROTECTED]> wrote: > > > On Sat, 03 May 2008 00:44:00 +1000 > > > Ben Finney <[EMAIL PROTECTED]<[EMAIL PROTECTED]>> > wrote: > > >> "D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > > >> > As someone else pointed out, not all the world is Linux. > > >> > > >> It's a good thing I've never implied such to be the case. > > > > > > You haven't *said* it but you have definitely *implied* it. > > > Installing Python in /usr/bin is not common. > > > > It is common. That's where it's installed by almost all Linux > > distributions. > > MacOS X system python (or links to them) is in the same place. > > -- > -- Lou Pecora > -- > http://mail.python.org/mailman/listinfo/python-list > -- | _ | * | _ | | _ | _ | * | | * | * | * | -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
In article <[EMAIL PROTECTED]>, Grant Edwards <[EMAIL PROTECTED]> wrote: > On 2008-05-02, D'Arcy J.M. Cain <[EMAIL PROTECTED]> wrote: > > On Sat, 03 May 2008 00:44:00 +1000 > > Ben Finney <[EMAIL PROTECTED]> wrote: > >> "D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > >> > As someone else pointed out, not all the world is Linux. > >> > >> It's a good thing I've never implied such to be the case. > > > > You haven't *said* it but you have definitely *implied* it. > > Installing Python in /usr/bin is not common. > > It is common. That's where it's installed by almost all Linux > distributions. MacOS X system python (or links to them) is in the same place. -- -- Lou Pecora -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Hallöchen! Gabriel Genellina writes: > [...] > > I can't believe some angry responses in this thread - it's just a > technical question, not about which is the best team in the > [preferred sports here] National Championship... Well, Python-list is tunnelled to Usenet. Welcome here. ;-) Tschö, Torsten. -- Torsten Bronger, aquisgrana, europa vetus Jabber ID: [EMAIL PROTECTED] (See http://ime.webhop.org for further contact info.) -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Ben Finney <[EMAIL PROTECTED]> writes: > The shebang line (the initial line of the file beginning with "#!") > takes advantage of OS kernels that determine how to execute a file > based on the first few bytes of the file. The shebang line tells the > kernel that this file should be executed by passing it as input to a > process started by another command. > > The specified command takes the form of a fully-qualified file path, > and zero or one arguments to the program. That command is then > executed by the kernel, and the Python program file is passed as > input to the resulting process. As was pointed out later in the thread, this description is partially untrue. The program isn't passed as input to the interpreter. Instead, the path to the program is appended as a command-line argument to the interpreter. Thus the kernel starts a command of the form: Examples: filename: /home/foo/bar.py shebang line: #! /usr/bin/python command line invoked: /usr/bin/python /home/foo/bar.py filename: /home/foo/Makefile shebang line: #! /usr/bin/make -f command line invoked: /usr/bin/make -f /home/foo/Makefile For more information on shebang processing, see http://foldoc.org/index.cgi?shebang> for a basic description, and http://www.in-ulm.de/~mascheck/various/shebang/> for lots of gory detail. -- \ "There's no excuse to be bored. Sad, yes. Angry, yes. | `\Depressed, yes. Crazy, yes. But there's no excuse for boredom, | _o__) ever." -- Viggo Mortensen | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
En Fri, 02 May 2008 12:07:55 -0300, D'Arcy J.M. Cain <[EMAIL PROTECTED]> escribió: On Sat, 03 May 2008 00:43:02 +1000 Ben Finney <[EMAIL PROTECTED]> wrote: Roy Smith <[EMAIL PROTECTED]> writes: > Have you ever shipped software to a customer? Yes, and all parties have been quite happy with the results. When some of us talk about shipping software we aren't talking about a 20 line script delivered to our uncle's construction company office. We are talking about millions of lines of code in thousands of programs and modules that has to run out of the box on whatever system the client happens to run on. [...] Simple for your 20 line single script. Not so simple for my million line, integrated system that has to work everywhere. In that case you have a setup script, I presume. You use distutils or a better alternative, I presume. You use the scripts= argument to setup, or the install_scripts distutils command, I presume. The first line on your scripts starts with #! and contains the word python somewhere, I presume. Then, distutils will adjust that shebang line using the same python executable that was used to run the installation. It doesn't matter whether the line read #!/usr/bin/python, #!/usr/bin/env python, #~/bin/python2.3 or just #!python: whatever Python was used to install your program, that will be written as the first line on the script, and consequentely that will be used to execute the script in the future. So the admin (or whoever installs the system) only has to make sure to use the right Python version from the right directory. That's all. Plain easy, isn't it? I can't believe some angry responses in this thread - it's just a technical question, not about which is the best team in the [preferred sports here] National Championship... -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
"D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > On Sat, 03 May 2008 00:43:02 +1000 > Ben Finney <[EMAIL PROTECTED]> wrote: > > Roy Smith <[EMAIL PROTECTED]> writes: > > > Have you ever shipped software to a customer? > > > > Yes, and all parties have been quite happy with the results. > > When some of us talk about shipping software we aren't talking about > a 20 line script delivered to our uncle's construction company > office. Nor was I. Thanks for the condescension and straw-man attacks, but... > I do believe I am done with this thread. That's a relief. -- \ “He that would make his own liberty secure must guard even | `\ his enemy from oppression.” —Thomas Paine | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Yves Dorfsman wrote: On UNIX, some people use #!/usr/bin/env python While other use #!/usr/bin/python Why is one preferred over the other one ? Caveat: I've only read *most* of this thread, so maybe someone else has already made the following point. It depends on the context. Ultimately, when your script is installed, it (almost certainly) should point to the precise Python executable the installer intends it to run on. One of the features of distutils is that it will *rewrite* "#!/usr/bin/env python" to use the exact executable that the installer used to execute the setup.py. So *as a developer* I recommend writing your scripts with "#!/usr/bin/env python". This lets distutils select the correct executable, and it lets your users play around with your scripts prior to installation without needing to rewrite the shebang line manually. I hate trying out someone's code just to find that that they hardcoded /usr/local/bin/python2.3. If you aren't using distutils to install for some reason, you might want to recommend that the installer change the shebang line in your installation instructions. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Ben Finney wrote: No, because it's quite common for the PATH variable to have '/usr/local/bin' appear *before* both of '/bin' and '/usr/bin'. If the system has a sysadmin-installed '/usr/local/bin/python' installed as well as the OS-installed '/usr/bin/python', then the two shebang options the OP raised will behave differently on such a system. This seems to be quite the point of the discussion. Yes, and that's the reason the env form is preferred. If someone -- either the system administrator, or the user environment, or the person executing the program on the fly -- has changed the PATH, they did it for a reason. If /usr/local/bin is in the PATH before /usr/bin, then that is a deliberate choice (whether system-wide or not) to prefer executables in /usr/local/bin to those in /usr/bin, and that is being done for a very conscious reason. Which is why the PATH exists in the first place, and why invoking the script with env is preferable. -- Erik Max Francis && [EMAIL PROTECTED] && http://www.alcyone.com/max/ San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On May 2, 11:07 am, "D'Arcy J.M. Cain" <[EMAIL PROTECTED]> wrote: > On Sat, 03 May 2008 00:43:02 +1000 > > Ben Finney <[EMAIL PROTECTED]> wrote: > > Roy Smith <[EMAIL PROTECTED]> writes: > > > Have you ever shipped software to a customer? > > > Yes, and all parties have been quite happy with the results. > > When some of us talk about shipping software we aren't talking about a > 20 line script delivered to our uncle's construction company office. We > are talking about millions of lines of code in thousands of programs and > modules that has to run out of the box on whatever system the client > happens to run on. If you're shipping a program that large you out to be packaging the Python interpreter with it. Frankly, this whole discussion is silly, as if it's some kind hard thing to open the script with a text editor and modify the shbang line. Carl Banks > > > Customer: "I can't install it there because > > reason the customer has>. If you can't make your product work > > > without requiring me to install python in /usr/bin, I'm afraid I > > > can't buy your product". > > > At this point they have the simple option of running the program with > > 'python /path/to/the/program'. It's certainly not a case of "can't > > make the product work". > > Simple for your 20 line single script. Not so simple for my million > line, integrated system that has to work everywhere. > > > It is, however, a case of "can't automatically account for every local > > customisation sysadmins choose to make on their systems". Perfectly > > willing to work with them to get their specific environment working, > > but as a matter of simple economics it's not worth my time to attempt > > to make such corner cases work automatically. > > If by "corner case" you mean "some system that I don't personally run" > then OK but to some of us your system is the corner case and we would > like our code to run there as well. > > Real software has to deal with the fact that support costs money. > You may be able to deal with one or two clients that way but that does > not scale very well. > > > If they've already chosen to install Python to some unpredictable > > location, they know what they're doing enough to invoke the program in > > a specific way to get it working. > > Unpredictable to you. Perfectly predictable on their system. > > I do believe I am done with this thread. > > -- > D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three > wolveshttp://www.druid.net/darcy/ | and a sheep voting on > +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
* Ben Finney (Sat, 03 May 2008 00:37:45 +1000)
> Thorsten Kampe <[EMAIL PROTECTED]> writes:
> > * Ben Finney (Fri, 02 May 2008 23:30:01 +1000)
> > > The OP was asking why people prefer on over the other. My answer
> > > is that I prefer specifying "give me the default OS Python"
> > > because anything not installed by the OS is to non-standardised
> > > for me to worry about.
> > >
> > > Others may prefer something different, but then they get to wear
> > > whatever problems occur as a result of that choice. I continue to
> > > be bemused by that preference, and nothing that I've seen so far
> > > in this thread illuminates the issue more.
> >
> > You're missing the point. Apart from the really dubious terms you
> > use ("OS installable package"), using env in the first line has
> > exactly the effect to use the default path of Python (which is the
> > first entry in your path)
>
> No, because it's quite common for the PATH variable to have
> '/usr/local/bin' appear *before* both of '/bin' and '/usr/bin'.
>
> If the system has a sysadmin-installed '/usr/local/bin/python'
> installed as well as the OS-installed '/usr/bin/python', then the two
> shebang options the OP raised will behave differently on such a
> system. This seems to be quite the point of the discussion.
Again you're missing the point. If you or whoever installs Python (or
another version of Python) to /usr/local/bin and puts this in the path
to front (as it's often done) then /you/ want that Python to be the
"default" one. It would just be silly to say "no, I the developer want
/usr/bin/python".
So in general "#! env" is better while in certain circumstance
hardcoding the path to /usr/bin/python can be better.
Thorsten
--
http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Thanks everybody, I didn't mean to start a flamewar... I do get it now, it's whatever python is in the path, vs. the specific one you're pointing to. Ben Finney wrote: No, because it's quite common for the PATH variable to have '/usr/local/bin' appear *before* both of '/bin' and '/usr/bin'. If the system has a sysadmin-installed '/usr/local/bin/python' installed as well as the OS-installed '/usr/bin/python', then the two shebang options the OP raised will behave differently on such a system. This seems to be quite the point of the discussion. And I have to admit, I prefer specifying the version (full path) because I have run into too many problem when users have different PATHs and end up running different version of an interpreter. Yves. -- http://www.SollerS.ca -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On 2008-05-02, D'Arcy J.M. Cain <[EMAIL PROTECTED]> wrote: > On Sat, 03 May 2008 00:44:00 +1000 > Ben Finney <[EMAIL PROTECTED]> wrote: >> "D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: >> > As someone else pointed out, not all the world is Linux. >> >> It's a good thing I've never implied such to be the case. > > You haven't *said* it but you have definitely *implied* it. > Installing Python in /usr/bin is not common. It is common. That's where it's installed by almost all Linux distributions. > It is very specific to your system. Are you claiming that Linux is not a "common" Unix-like OS? -- Grant -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On Sat, 03 May 2008 00:43:02 +1000 Ben Finney <[EMAIL PROTECTED]> wrote: > Roy Smith <[EMAIL PROTECTED]> writes: > > Have you ever shipped software to a customer? > > Yes, and all parties have been quite happy with the results. When some of us talk about shipping software we aren't talking about a 20 line script delivered to our uncle's construction company office. We are talking about millions of lines of code in thousands of programs and modules that has to run out of the box on whatever system the client happens to run on. > > Customer: "I can't install it there because > reason the customer has>. If you can't make your product work > > without requiring me to install python in /usr/bin, I'm afraid I > > can't buy your product". > > At this point they have the simple option of running the program with > 'python /path/to/the/program'. It's certainly not a case of "can't > make the product work". Simple for your 20 line single script. Not so simple for my million line, integrated system that has to work everywhere. > It is, however, a case of "can't automatically account for every local > customisation sysadmins choose to make on their systems". Perfectly > willing to work with them to get their specific environment working, > but as a matter of simple economics it's not worth my time to attempt > to make such corner cases work automatically. If by "corner case" you mean "some system that I don't personally run" then OK but to some of us your system is the corner case and we would like our code to run there as well. Real software has to deal with the fact that support costs money. You may be able to deal with one or two clients that way but that does not scale very well. > If they've already chosen to install Python to some unpredictable > location, they know what they're doing enough to invoke the program in > a specific way to get it working. Unpredictable to you. Perfectly predictable on their system. I do believe I am done with this thread. -- D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On Sat, 03 May 2008 00:44:00 +1000 Ben Finney <[EMAIL PROTECTED]> wrote: > "D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > > As someone else pointed out, not all the world is Linux. > > It's a good thing I've never implied such to be the case. You haven't *said* it but you have definitely *implied* it. Installing Python in /usr/bin is not common. It is very specific to your system. -- D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Hallöchen! D'Arcy J.M. Cain writes: > On Fri, 02 May 2008 16:26:51 +0200 > Torsten Bronger <[EMAIL PROTECTED]> wrote: > >>> Certainly #! /usr/bin/python is fine if you never expect your >>> software to run outside of your own little corner of the world >>> but you asked why people prefer the env version and the answer >>> is that we want to write software that runs everywhere that >>> Python runs. >> >> Granted, but you must draw the line somewhere anyway. I cannot > > No one is talking about if statements here. Sorry to become laconical, but your reply was so, too: http://en.wikipedia.org/wiki/Abstraction Tschö, Torsten. -- Torsten Bronger, aquisgrana, europa vetus Jabber ID: [EMAIL PROTECTED] (See http://ime.webhop.org for further contact info.) -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On Fri, 02 May 2008 16:26:51 +0200 Torsten Bronger <[EMAIL PROTECTED]> wrote: > > Certainly #! /usr/bin/python is fine if you never expect your > > software to run outside of your own little corner of the world but > > you asked why people prefer the env version and the answer is that > > we want to write software that runs everywhere that Python runs. > > Granted, but you must draw the line somewhere anyway. I cannot No one is talking about if statements here. -- D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On 2008-05-02, Jeroen Ruigrok van der Werven <[EMAIL PROTECTED]> wrote: > -On [20080502 07:51], Ben Finney ([EMAIL PROTECTED]) wrote: >>To my mind, the Python interpreter installed by a package as >>distributed with the OS *is* OS territory and belongs in /usr/bin/. > > That's the difference with a distribution, such as Linux, and full OSes , > such as BSDs or commercial Unix variants. They prefer to keep a pristine > state for the OS vendor files Python _is_ an OS vendor file in the Linux world. > versus what the user can opt to install himself, Traditionally, Python has not been optional. > hence the /usr/bin - /usr/local/bin separation. Same for sbin, > lib, and so on. It effectively guarantees you can nuke > /usr/local without ill consequences for your OS. That's the point. You _couldn't_ nuke Python and have your system keep running. That's why it was in /usr/bin. -- Grant -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On 2008-05-02, Jeroen Ruigrok van der Werven <[EMAIL PROTECTED]> wrote: >>I've never clearly understood why people want to use "#! /usr/bin/env >>python", which is prone to finding a different Python from the one >>installed by the operating system. I'd be interested to see what >>responses are in favour of it, and what the reasoning is. > > Simple, some systems are not as peculiar as a lot of Linux boxes which > chug everything into /usr/bin, which is OS territory On many Linux distros, Python is pretty much part of the OS. Since the early days of RedHat, Python has been part of the base/minimum install since a lot of the "required" system utilities were written in python. In Redhat, the package manger was originally written in Python, so Python had to be in "OS territory". > (as has been decreed long ago by hier(7)), but rather use > /usr/local/bin (all BSD Unix and derivatives) or /opt or > whatever convention a particular operating system has. In the Linux world, /usr/local/bin and /opt are for stuff installed by the user, not stuff that is an integral, required part of the OS distribution. -- Grant -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
"D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > On Fri, 02 May 2008 23:30:01 +1000 > Ben Finney <[EMAIL PROTECTED]> wrote: > > The OP was asking why people prefer on over the other. My answer > > is that I prefer specifying "give me the default OS Python" > > because anything not installed by the OS is [too] non-standardised > > for me to worry about. > > As someone else pointed out, not all the world is Linux. It's a good thing I've never implied such to be the case. -- \ "If nature has made any one thing less susceptible than all | `\others of exclusive property, it is the action of the thinking | _o__) power called an idea" -- Thomas Jefferson | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Roy Smith <[EMAIL PROTECTED]> writes: > In article <[EMAIL PROTECTED]>, > Ben Finney <[EMAIL PROTECTED]> wrote: > > > Whereas if Python is *not* installed from an OS package, it's up > > to the sys admin to ensure that it works -- not up to my program. > > So I don't see the point in making it work by default, when what I > > want for my program is that it works *with the default Python*, > > not with some non-default installation. > > Ben, > > Have you ever shipped software to a customer? Yes, and all parties have been quite happy with the results. > Imagine the following conversation: > > Customer: "Your product is broken. It says it can't find python, and > I know I have it installed". > > Vendor: "Where do you have it installed?" > > Customer: "In /opt/bin/python" > > Vendor: "Oh, that's your problem, it HAS to be in /usr/bin/python". At this point the vendor isn't me, because this statement isn't true. See below. > Customer: "I can't install it there because reason the customer has>. If you can't make your product work > without requiring me to install python in /usr/bin, I'm afraid I > can't buy your product". At this point they have the simple option of running the program with 'python /path/to/the/program'. It's certainly not a case of "can't make the product work". It is, however, a case of "can't automatically account for every local customisation sysadmins choose to make on their systems". Perfectly willing to work with them to get their specific environment working, but as a matter of simple economics it's not worth my time to attempt to make such corner cases work automatically. > If you want to hard-code /usr/bin/python into your application, > that's your decision. If you would like to take on the task of > convincing every sysadmin in the world to do things the way you > think they should be done, have fun. If they've already chosen to install Python to some unpredictable location, they know what they're doing enough to invoke the program in a specific way to get it working. -- \ Rommel: "Don't move, or I'll turn the key on this can of Spam!" | `\ -- The Goon Show, _Rommel's Treasure_ | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On 2008-05-02, Ben Finney <[EMAIL PROTECTED]> wrote: > The specified command takes the form of a fully-qualified file > path, and zero or one arguments to the program. That command > is then executed by the kernel, and the Python program file is > passed as input to the resulting process. Just to clarify that a bit a little, the name of the file (as it was given to the "exec" system call) containing the "shebang line" is passed to the resulting process as a command-line parameter. >> Why is one preferred over the other one ? > > I've never clearly understood why people want to use "#! /usr/bin/env > python", which is prone to finding a different Python from the one > installed by the operating system. I'd be interested to see what > responses are in favour of it, and what the reasoning is. > > One possible reason is that the programmer is attempting to allow for > systems where Python has been installed, but not from an operating > system package. Exactly. the "env" approach works as long as python is installed somewhere on the PATH. "#!/usr/bin/python" will fail if python is installed in /usr/local/bin/python. -- Grant -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Thorsten Kampe <[EMAIL PROTECTED]> writes:
> * Ben Finney (Fri, 02 May 2008 23:30:01 +1000)
> > The OP was asking why people prefer on over the other. My answer
> > is that I prefer specifying "give me the default OS Python"
> > because anything not installed by the OS is to non-standardised
> > for me to worry about.
> >
> > Others may prefer something different, but then they get to wear
> > whatever problems occur as a result of that choice. I continue to
> > be bemused by that preference, and nothing that I've seen so far
> > in this thread illuminates the issue more.
>
> You're missing the point. Apart from the really dubious terms you
> use ("OS installable package"), using env in the first line has
> exactly the effect to use the default path of Python (which is the
> first entry in your path)
No, because it's quite common for the PATH variable to have
'/usr/local/bin' appear *before* both of '/bin' and '/usr/bin'.
If the system has a sysadmin-installed '/usr/local/bin/python'
installed as well as the OS-installed '/usr/bin/python', then the two
shebang options the OP raised will behave differently on such a
system. This seems to be quite the point of the discussion.
--
\ "Time's fun when you're having flies." -- Kermit the Frog |
`\ |
_o__) |
Ben Finney
--
http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Hallöchen! D'Arcy J.M. Cain writes: > On Fri, 02 May 2008 23:30:01 +1000 > Ben Finney <[EMAIL PROTECTED]> wrote: > >> The OP was asking why people prefer on over the other. My answer >> is that I prefer specifying "give me the default OS Python" >> because anything not installed by the OS is to non-standardised >> for me to worry about. > > [...] > > Certainly #! /usr/bin/python is fine if you never expect your > software to run outside of your own little corner of the world but > you asked why people prefer the env version and the answer is that > we want to write software that runs everywhere that Python runs. Granted, but you must draw the line somewhere anyway. I cannot pollute my program with hundreds of if clauses just to make it work on every quirky system. It's the *systems* where the streamlining must happen, not the programs. Tschö, Torsten. -- Torsten Bronger, aquisgrana, europa vetus Jabber ID: [EMAIL PROTECTED] (See http://ime.webhop.org for further contact info.) -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On Fri, 02 May 2008 23:30:01 +1000 Ben Finney <[EMAIL PROTECTED]> wrote: > The OP was asking why people prefer on over the other. My answer is > that I prefer specifying "give me the default OS Python" because > anything not installed by the OS is to non-standardised for me to > worry about. As someone else pointed out, not all the world is Linux. So your version of Linux (I'm not sure whether it is true for all versions or not) delivers Python as part of the OS. That is simply not true of the whole world. Some OS distributions have an adjunct facility for installing packages but they are not part of the OS. Some systems don't even have that and people must download packages such as Python and install them manually. Even on Linux there are people who won't install binaries and use NetBSD's pkgsrc instead. Clearly that cannot install into /usr/bin since it is not part of the OS. Certainly #! /usr/bin/python is fine if you never expect your software to run outside of your own little corner of the world but you asked why people prefer the env version and the answer is that we want to write software that runs everywhere that Python runs. -- D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
In article <[EMAIL PROTECTED]>, Ben Finney <[EMAIL PROTECTED]> wrote: > Whereas if Python is *not* installed from an OS package, it's up to > the sys admin to ensure that it works -- not up to my program. So I > don't see the point in making it work by default, when what I want for > my program is that it works *with the default Python*, not with some > non-default installation. Ben, Have you ever shipped software to a customer? Imagine the following conversation: Customer: "Your product is broken. It says it can't find python, and I know I have it installed". Vendor: "Where do you have it installed?" Customer: "In /opt/bin/python" Vendor: "Oh, that's your problem, it HAS to be in /usr/bin/python". Customer: "I can't install it there because . If you can't make your product work without requiring me to install python in /usr/bin, I'm afraid I can't buy your product". Vendor: "No problem sir, I'll be happy to tell our sales folks to stop bothering you". If you want to hard-code /usr/bin/python into your application, that's your decision. If you would like to take on the task of convincing every sysadmin in the world to do things the way you think they should be done, have fun. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
* Ben Finney (Fri, 02 May 2008 23:30:01 +1000)
> The OP was asking why people prefer on over the other. My answer is
> that I prefer specifying "give me the default OS Python" because
> anything not installed by the OS is to non-standardised for me to
> worry about.
>
> Others may prefer something different, but then they get to wear
> whatever problems occur as a result of that choice. I continue to be
> bemused by that preference, and nothing that I've seen so far in this
> thread illuminates the issue more.
You're missing the point. Apart from the really dubious terms you use
("OS installable package"), using env in the first line has exactly the
effect to use the default path of Python (which is the first entry in
your path) and not some hard-coded path (which might not even exist).
Thorsten
--
http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
"D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > On Fri, 02 May 2008 13:24:01 +1000 > Ben Finney <[EMAIL PROTECTED]> wrote: > > I much prefer "#! /usr/bin/python" because I want my Python > > programs to, by default, be run with the default Python, and > > depend on Python being installed by the operating system's package > > manager. On systems that use shebang lines and that actually have > > standardised filesystem locations, the default Python is found at > > '/usr/bin/python'. > > You have lived a sheltered life. Not every packaging system puts the > executible in /usr/bin. Many systems use /usr/local/bin. "D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > On Fri, 02 May 2008 15:50:22 +1000 > Ben Finney <[EMAIL PROTECTED]> wrote: > > They use that for the operating-system-installed default Python > > interpreter? Colour me incredulous. > > OK, let me get out my crayons. However, note that I did not say > "operating-system-installed." That is, however, the context I've been explicitly using since this sub-thread began. The OP was asking why people prefer on over the other. My answer is that I prefer specifying "give me the default OS Python" because anything not installed by the OS is to non-standardised for me to worry about. Others may prefer something different, but then they get to wear whatever problems occur as a result of that choice. I continue to be bemused by that preference, and nothing that I've seen so far in this thread illuminates the issue more. -- \ "Nothing so needs reforming as other people's habits." -- Mark | `\ Twain, _Pudd'n'head Wilson_ | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On Fri, 02 May 2008 15:50:22 +1000 Ben Finney <[EMAIL PROTECTED]> wrote: > > You have lived a sheltered life. Not every packaging system puts the > > executible in /usr/bin. Many systems use /usr/local/bin. > > They use that for the operating-system-installed default Python > interpreter? Colour me incredulous. OK, let me get out my crayons. However, note that I did not say "operating-system-installed." I said a packaging system puts it there. In fact, the NetBSD packaging system works on many systems including Linux and thus is not an operating system packager. -- D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Jeroen Ruigrok van der Werven <[EMAIL PROTECTED]> writes: > -On [20080502 07:51], Ben Finney ([EMAIL PROTECTED]) wrote: > >To my mind, the Python interpreter installed by a package as > >distributed with the OS *is* OS territory and belongs in /usr/bin/. > > That's the difference with a distribution, such as Linux, and full > OSes , such as BSDs or commercial Unix variants. They prefer to keep > a pristine state for the OS vendor files versus what the user can > opt to install himself, hence the /usr/bin - /usr/local/bin > separation. Fine so far. /usr/local/ is certainly for "what the (system administrator) user opts to install themselves". > It effectively guarantees you can nuke /usr/local without ill > consequences for your OS. You say this as though it's a property that a GNU/Linux distribution doesn't have. But the "keep /usr/local/ untouched by OS packages" approach taken by GNU/Linux *also* means that /usr/local/ can be blown away without ill consequences for the OS. So I don't see why you draw that distinction here. The difference seems to be that Python is an OS-installable package on GNU/Linux, and thus gets installed to the OS-packaged location. So the default Python installation should work. Whereas if Python is *not* installed from an OS package, it's up to the sys admin to ensure that it works -- not up to my program. So I don't see the point in making it work by default, when what I want for my program is that it works *with the default Python*, not with some non-default installation. -- \ "Truth is stranger than fiction, but it is because fiction is | `\ obliged to stick to possibilities, truth isn't." -- Mark | _o__) Twain, _Following the Equator_ | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Yves Dorfsman <[EMAIL PROTECTED]> wrote: > On UNIX, some people use > #!/usr/bin/env python > > While other use > #!/usr/bin/python > > Why is one preferred over the other one ? > I don't think the answers so far have communicated what I believe to be the important point: it isn't that one is always better than the other, it depends on what you are trying to achieve. The first one runs the Python found from the environment. This means you can write a script and expect it to run on systems configured differently. You might prefer in some cases to specify a particular version of Python: #!/usr/bin/env python2.5 The second one runs a specific copy of Python (and here it is even more likely that you'll want to specify a particular version). This is important if your program is being run as a service or some other background situation where the environment isn't set up. For example Subversion hooks all run with an empty environment, and cron jobs run with a default environment which may not include python (e.g. if it is in /usr/local/bin). -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
-On [20080502 07:51], Ben Finney ([EMAIL PROTECTED]) wrote: >To my mind, the Python interpreter installed by a package as >distributed with the OS *is* OS territory and belongs in /usr/bin/. That's the difference with a distribution, such as Linux, and full OSes , such as BSDs or commercial Unix variants. They prefer to keep a pristine state for the OS vendor files versus what the user can opt to install himself, hence the /usr/bin - /usr/local/bin separation. Same for sbin, lib, and so on. It effectively guarantees you can nuke /usr/local without ill consequences for your OS. Different philosophies, but after having spent more than 10+ years on too many Unix and Unix-like systems I know the importance of platform portability a bit too much and hardcoding a shebang sequence is not the solution in general. Using env is the, arguably, best solution available. -- Jeroen Ruigrok van der Werven / asmodai イェルーン ラウフロック ヴァン デル ウェルヴェン http://www.in-nomine.org/ | http://www.rangaku.org/ | GPG: 2EAC625B Felix, qui potuit rerum cognoscere causas... -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
"D'Arcy J.M. Cain" <[EMAIL PROTECTED]> writes: > On Fri, 02 May 2008 13:24:01 +1000 > Ben Finney <[EMAIL PROTECTED]> wrote: > > I much prefer "#! /usr/bin/python" because I want my Python > > programs to, by default, be run with the default Python, and > > depend on Python being installed by the operating system's package > > manager. On systems that use shebang lines and that actually have > > standardised filesystem locations, the default Python is found at > > '/usr/bin/python'. > > You have lived a sheltered life. Not every packaging system puts the > executible in /usr/bin. Many systems use /usr/local/bin. They use that for the operating-system-installed default Python interpreter? Colour me incredulous. -- \ “[The RIAA] have the patience to keep stomping. They’re | `\playing whack-a-mole with an infinite supply of tokens.” | _o__) —kennon, http://kuro5hin.org/ | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Jeroen Ruigrok van der Werven <[EMAIL PROTECTED]> writes: > -On [20080502 05:26], Ben Finney ([EMAIL PROTECTED]) wrote: > >I've never clearly understood why people want to use "#! > >/usr/bin/env python", which is prone to finding a different Python > >from the one installed by the operating system. I'd be interested > >to see what responses are in favour of it, and what the reasoning > >is. > > Simple, some systems are not as peculiar as a lot of Linux boxes > which chug everything into /usr/bin, which is OS territory (as has > been decreed long ago by hier(7)), but rather use /usr/local/bin > (all BSD Unix and derivatives) or /opt or whatever convention a > particular operating system has. To my mind, the Python interpreter installed by a package as distributed with the OS *is* OS territory and belongs in /usr/bin/. > As such, your script with #!/usr/bin/python is as bad as an ash > shell script with #!/bin/bash. Clearly if the program is written to be interpreted by the Ash shell, it should not declare Bash as the interpreter. I don't see how declaring Python as the interpreter for a Python program is supposed to be "as bad" as that. -- \ "Don't be afraid of missing opportunities. Behind every failure | `\ is an opportunity somebody wishes they had missed." -- Jane | _o__) Wagner, via Lily Tomlin | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Yves Dorfsman <[EMAIL PROTECTED]> wrote: > >On UNIX, some people use >#!/usr/bin/env python > >While other use >#!/usr/bin/python > >Why is one preferred over the other one ? The /usr/bin/env solution finds the Python interpreter anywhere on the PATH, whether it be /usr/bin or /usr/local/bin, or whatever. With /usr/bin/python, it MUST be in /usr/bin. Way back when, Python wasn't included in Linux distributions by default, so it was difficult to predict where it would be. /usr/bin/env, on the other hand, is well-established at that location. These days, since Python is nearly ubiquitous, I suspect it is not so important. -- Tim Roberts, [EMAIL PROTECTED] Providenza & Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
-On [20080502 05:26], Ben Finney ([EMAIL PROTECTED]) wrote: >I've never clearly understood why people want to use "#! /usr/bin/env >python", which is prone to finding a different Python from the one >installed by the operating system. I'd be interested to see what >responses are in favour of it, and what the reasoning is. Simple, some systems are not as peculiar as a lot of Linux boxes which chug everything into /usr/bin, which is OS territory (as has been decreed long ago by hier(7)), but rather use /usr/local/bin (all BSD Unix and derivatives) or /opt or whatever convention a particular operating system has. And prone to find the wrong Python, it all depends upon proper $PATH administration. As such, your script with #!/usr/bin/python is as bad as an ash shell script with #!/bin/bash. #!/usr/bin/env python is more cross-OS friendly, there's more than just Linux you know. -- Jeroen Ruigrok van der Werven / asmodai イェルーン ラウフロック ヴァン デル ウェルヴェン http://www.in-nomine.org/ | http://www.rangaku.org/ | GPG: 2EAC625B I dream of Love as Time runs through my hand... -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
On Fri, 02 May 2008 13:24:01 +1000 Ben Finney <[EMAIL PROTECTED]> wrote: > I much prefer "#! /usr/bin/python" because I want my Python programs > to, by default, be run with the default Python, and depend on Python > being installed by the operating system's package manager. On systems > that use shebang lines and that actually have standardised filesystem > locations, the default Python is found at '/usr/bin/python'. You have lived a sheltered life. Not every packaging system puts the executible in /usr/bin. Many systems use /usr/local/bin. NetBSD uses /usr/pkg/bin but allows you to define your own pkg root. Using /usr/bin/env allows your code to run on all these systems. -- D'Arcy J.M. Cain <[EMAIL PROTECTED]> | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
In article <[EMAIL PROTECTED]>, Ben Finney <[EMAIL PROTECTED]> wrote: > I've never clearly understood why people want to use "#! /usr/bin/env > python", which is prone to finding a different Python from the one > installed by the operating system. I'd be interested to see what > responses are in favour of it, and what the reasoning is. > > One possible reason is that the programmer is attempting to allow for > systems where Python has been installed, but not from an operating > system package. You've got it exactly. I'm currently using Python to write unit tests as part of a build system. Many of our development boxes don't have python installed in /usr/bin (or perhaps at all). And even if they did, we might want to use a different version of Python on different branches of the code. We've got Python built for all our platforms and the binaries stored in our source control system. When you check out a particular branch, you get the right version of Python for that branch. By having the Python scripts start with #!/usr/bin/env python, I can select the version of Python I want just by changing the environment. Then, of course, I recently ran across a machine where env was installed in /opt/gnu/bin instead of /usr/bin. Sigh. Sometimes you just can't win. -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
Yves Dorfsman <[EMAIL PROTECTED]> writes: > On UNIX, some people use > #!/usr/bin/env python > > While other use > #!/usr/bin/python You haven't indicated your understanding of what the difference in meaning is, so I'll explain it for those who might not know. The shebang line (the initial line of the file beginning with "#!") takes advantage of OS kernels that determine how to execute a file based on the first few bytes of the file. The shebang line tells the kernel that this file should be executed by passing it as input to a process started by another command. The specified command takes the form of a fully-qualified file path, and zero or one arguments to the program. That command is then executed by the kernel, and the Python program file is passed as input to the resulting process. The difference between the two is thus what command is executed to interpret the Python program. * "#! /usr/bin/env python" will run the command "/usr/bin/env python". The 'env(1)' manual page says its purpose is to "run a program in a modified environment", but it also has the effect that the command is searched on the current PATH variable, and executed based on the first occurrence. * "#! /usr/bin/python" will run the command "/usr/bin/python", which is of course the system Python instance as installed by most OS packaging systems. That command is run, and the result is the Python interpreter. > Why is one preferred over the other one ? I've never clearly understood why people want to use "#! /usr/bin/env python", which is prone to finding a different Python from the one installed by the operating system. I'd be interested to see what responses are in favour of it, and what the reasoning is. One possible reason is that the programmer is attempting to allow for systems where Python has been installed, but not from an operating system package. I much prefer "#! /usr/bin/python" because I want my Python programs to, by default, be run with the default Python, and depend on Python being installed by the operating system's package manager. On systems that use shebang lines and that actually have standardised filesystem locations, the default Python is found at '/usr/bin/python'. -- \ "Any sufficiently advanced bug is indistinguishable from a | `\ feature." —Rich Kulawiec | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
The first method allows python to be installed in an alternate location (i.e. /usr/local/bin). "env" in this case is being used to launch python from whatever location python is installed to. I like to think of it as an "abstraction" of the python location to make it "multiplatform-friendly" since not all Unix systems put python in /usr/bin. On Fri, May 2, 2008 at 1:36 AM, Yves Dorfsman <[EMAIL PROTECTED]> wrote: > On UNIX, some people use > #!/usr/bin/env python > > While other use > #!/usr/bin/python > > Why is one preferred over the other one ? > > Thanks. > > -- > Yves. > http://www.SollerS.ca > -- > http://mail.python.org/mailman/listinfo/python-list > -- Computers are like air conditioners... They quit working when you open Windows. -- http://mail.python.org/mailman/listinfo/python-list
#!/usr/bin/env python vs. #!/usr/bin/python
On UNIX, some people use #!/usr/bin/env python While other use #!/usr/bin/python Why is one preferred over the other one ? Thanks. -- Yves. http://www.SollerS.ca -- http://mail.python.org/mailman/listinfo/python-list
