"On interrupt." Used in shell scripts to handle interrupt signals
(similar to the Bourne shell's trap 2 and trap "" 2 commands).
The first form is like a goto
label. The script will
label: if it catches an interrupt signal (e.g., CTRL-C).
The second form lets the script ignore interrupts. This is useful
at the beginning of a script or before any code segment that needs
to run unhindered (e.g., when moving files).
The third form restores interrupt handling that was previously disabled
with onintr -.
onintr cleanup # go to "cleanup" on interrupt . . # shell script commands . cleanup: # label for interrupts onintr - # ignore additional interrupts rm -f $tmpfiles # remove any files created exit 2 # exit with an error status