z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

trap
Usage Note
Examples
Localization
Exit Values
Messages
Portability
command list again and runs the commands. A missing argument or an argument of
− (dash) resets the default trap condition. A null argument ('') causes the trap
condition to be ignored.
If there are no arguments at all, trap prints a list of all the traps and their
commands.
trap is a special built-in shell command.
1. On error or exit, this example deletes a temporary file created during command
execution.
trap ’rm –f /tmp/xyz$$; exit’ ERR EXIT
When an interrupt signal is received, the example prompts whether to abort,
and exits if the answer is y.
trap ’read REPLY?"ABORT??"
case $REPLY in
y) exit 1;;
esac’ 2
2. This example saves your shell history file (specified by the value you give the
HISTFILE environment variable) before timing you out, so you can restore it
when you log on again.
trap ’cp $HISTFILE $HOME/old_hist.bak; exit’ ALRM
trap uses the following localization environment variables:
v LANG
v LC_ALL
v LC_MESSAGES
v NLSPATH
See Appendix F for more information.
0 Successful completion
1 Failure due to any of the following:
v Incorrect signal name
v Incorrect signal number
2 Incorrect command-line argument
Possible error messages include:
name not a valid trap name
You specified an unrecognized trap name. The usual cause of this error is a
typing mistake on the command line.
POSIX.2, X/Open Portability Guide.
708 z/OS V1R9.0 UNIX System Services Command Reference