Re: [julia-users] running multiple commands
Julia doesn't use the shell to execute commands, but parses shell commands itself. Since Julia has its own control flow constructs, we don't duplicate those at the shell level. See http://julia.readthedocs.org/en/latest/manual/running-external-programs/#pipelines for more information. On Fri, Nov 7, 2014 at 9:03 PM, Davide Lasagna lasagnadav...@gmail.com wrote: Hi, just wondering why I cannot chain these kind of multiple commands in julia. Example: the command run(`mkdir $tmp touch $file`) creates the directories $tmp, touch and $file, while I only want the second part after to run if first command is successful. Similarly if I use the ; to create a sequence of commands, e.g. run(`mkdir $tmp; touch $file`). I could run multiple commands separately, and do the checks in julia, but there might be an easier way to achieve that. Davide
Re: [julia-users] running multiple commands
Thanks Stefan, As far as I can see from the docs, the pipe | can be used to chain commands where one would use a true pipe in the shell. So the examples like run(`cut -d: -f3 /etc/passwd` | `sort -n` | `tail -n5`) do make sense to me. However, it appears that if one wants to use operators like ; || in commands, one needs to implement the logic at the julia level. That is fine. However, I tried to cheat and used the pipe | to chain commands even tough I do not need or want redirection to occur. For instance: run(`touch a` | `sleep 3` | `touch b`) This example runs, but the three commands are executed at the same time as I see the two files a and b appearing at the same time in the file manager. Hence I deduce that | cannot be used to chain all king of commands. Am I right? Davide On Saturday, November 8, 2014 10:17:15 AM UTC, Stefan Karpinski wrote: Julia doesn't use the shell to execute commands, but parses shell commands itself. Since Julia has its own control flow constructs, we don't duplicate those at the shell level. See http://julia.readthedocs.org/en/latest/manual/running-external-programs/#pipelines for more information. On Fri, Nov 7, 2014 at 9:03 PM, Davide Lasagna lasagn...@gmail.com javascript: wrote: Hi, just wondering why I cannot chain these kind of multiple commands in julia. Example: the command run(`mkdir $tmp touch $file`) creates the directories $tmp, touch and $file, while I only want the second part after to run if first command is successful. Similarly if I use the ; to create a sequence of commands, e.g. run(`mkdir $tmp; touch $file`). I could run multiple commands separately, and do the checks in julia, but there might be an easier way to achieve that. Davide
Re: [julia-users] running multiple commands
It seems that implementing the logic at the Julia level could be as simple as success(`touch a`) success(`sleep 3`) success (`touch b`) Slightly more verbose, but not so much. Overloading is not possible (without a macro) due to the sort circuit characteristics.
[julia-users] running multiple commands
Hi, just wondering why I cannot chain these kind of multiple commands in julia. Example: the command run(`mkdir $tmp touch $file`) creates the directories $tmp, touch and $file, while I only want the second part after to run if first command is successful. Similarly if I use the ; to create a sequence of commands, e.g. run(`mkdir $tmp; touch $file`). I could run multiple commands separately, and do the checks in julia, but there might be an easier way to achieve that. Davide
