On Sun, Apr 05, 2015 at 09:39:50AM -0700, Scott Bronson wrote: > Hi, I don't understand the behavior of the trap command... > > echo ' > trap "echo $1" DEBUG > ' > ./trapcmd > > source ./trapcmd first > source ./trapcmd second > > I would expect the debug trap to now be 'echo second'. > However, it's still 'echo first' (full output below).
Without the source shenanigans, it works: imadev:~$ trap 'echo first' DEBUG imadev:~$ echo hi first hi imadev:~$ trap 'echo second' DEBUG first imadev:~$ echo hi second hi As soon as I try your source trick, things start to break down: imadev:~$ echo 'trap "echo $1" DEBUG' > foo second imadev:~$ source ./foo one second imadev:~$ echo hi second hi But if I clear the DEBUG trap first, then it starts to work: imadev:~$ trap - DEBUG second imadev:~$ echo hi hi imadev:~$ source ./foo one imadev:~$ echo hi one hi So, if there is a bug here, it's got something to do with setting traps in a sourced file, when that type of trap is already set. (Also, I didn't try with any other traps. Maybe it's specific to DEBUG.)
