xinyou yan wrote:
thank you !
As you write . It works . I thought it was captured by shell. In fact the error in cods. I am just a student . Someone told me some skills are import . However , I study it and find I can't use it right now . That lead careless .
May be we need to find interest in programming .
Sounds as if you have mastered: - ask a decent question - listen to the answer - understand what you were told
You have a good start, keep going.
2011/3/7 Cameron Simpsoncs@zip.com.au:
On 07Mar2011 10:17, xinyou yanyxy.716@gmail.com wrote: | I want to know when i use | | trap 'rm -f /tmp/my_tmp_file_$$' INT | | why shell itself capture the single and she shellscript exit.
But it doesn't!
The shell captures the signal, runs the rm command, and proceeds.
| Here is the code from<< Beginning Programming>> | #!/bin/sh | trap 'rm -f /tmp/my_tmp_file_$$' INT | echo creating file /tmp/my_tmp_file_$$ | date> /tmp/my_tmp_file_$$ | | echo "Press interrupt (Ctrl-C) to interrupt...." | while [ -f /tmp/my_tmp_file_$$ ]; do | echo File exists | sleep 1 | done | echo The file no longer exists
When I run this script, this all works just fine.
| trap INT
However, _this_ line above is incorrect. "trap" requires a shell command to run, even if it is empty. For example:
trap 'echo INT received' INT
From "man sh":
trap [-lp] [[arg] sigspec ...] The command arg is to be read and executed when the shell receives signal(s) sigspec. [...snip...] If arg is the null string the signal specified by each sigspec is ignored by the shell and by the commands it invokes. [...snip...]
When I run the script it aborts at that line.
Try changing that line to:
trap 'echo INT received' INT
and rerunning your script.
Cheers,
Cameron Simpsoncs@zip.com.au DoD#743 http://www.cskk.ezoshosting.com/cs/
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