On Mon, 12 Nov 2007 00:25:29 +0100, ropers <[EMAIL PROTECTED]> wrote:
xterm -e "telnet `echo ${1##telnet://}|sed -e 's/:/ /'`"
...
My .telnet4firefox.sh file now is:
#!/bin/sh
xterm -e "telnet `echo ${*##telnet://} | sed 's/:/ /g'`"
...
- I understand the backtick quoted execution.
- I *think* the {} bit is awk(1), but I'm not entirely clear how it
does what it does.
The ${var##string} part is ksh or bash specific, see "Parameter Expansion"
in the bash man page if you're using bash.
I see your #! line says /bin/sh but to my knowledge a "real" sh, not
emulated by bash or ksh doesn't support ${##} and friends, if I'm wrong
feel free to correct me. =)
What it does is cut away the string "telnet://" from the beginning of the
first positional parameter.
(You've changed that to * in your last example, don't know what will be
substituted for $* there if you have more than one positional argument
for your script, you might what to test that or change back to ${1} ).
- I think that the $* variable, which I think is somehow what the
${*##telnet://} bit is about, is the entire string of parameters
passed to the script. ($1 as in the previous examples would be the
first parameter only.)
Yes. $@ is also all the positional parameters, they expand differently
when expanded inside "". A full explaination can be found under "Special
Parameters" in the bash man page.
I'm not really happy with the way this is put together. If awk(1) can
remove telnet:// from $* (if present), then surely it should be able
to turn a colon (if present) into a space, right?
If I'd use a pipe, I'd pipe it to tr, not sed.
But I wouldn't, I'd let bash do it:
#!/bin/bash
IFS=:
set -- $1
host=${2##//}
port=$3
xterm -e "telnet $host $port"
This way, you won't need to use anything else than bash itself. =)
What it does is that it splits $1 using : as a delimiter and stores
the split parts into the positional arguments like this:
$1 = "telnet"
$2 = "//example.com"
$3 = "1991"
Then the host=${2##//} cuts away the "//" from $2 and stores in $host.
Yes, this is an opportunity for me to really start looking into
awk(1), but thus far I seem to be making little headway...
Awk is nice, but this isn't awk. ;)
Thanks again and kind regards,
--ropers
Hope it helps!
/ Linus
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