On 07Mar2011 10:17, xinyou yan yxy.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,