The loopwhilex program
loopwhilex performs a conditional loop.
loopwhilex [ -n ] [ -o okcodes | -x breakcodes ] prog...
- loopwhilex runs prog... as a child process and
waits for it to complete.
- As long as prog exits zero, loopwhile runs it again.
- loopwhilex then exits with an
approximation of the last prog
invocation's exit code.
- -o okcodes : okcodes must
be a comma-separated list of exit codes. loopwhilex will keep
looping as long as prog exits with one of the codes in
- -x breakcodes : like the previous
option, but with inverted meaning - the listed exit codes are codes
that will break the loop and exit, and the unlisted exit codes will keep
the loop running.
- -n : negate the test. This option is now redundant,
and may disappear soon.
- loopwhilex prog... is equivalent to loopwhilex -n -x 0 prog...
and loopwhilex -o 0 prog...
- Be careful: execline maintains no state, in particular it
uses no real variables, and environment will
be of no use here since every instance of prog... runs as a separate
child process. To avoid being stuck in an infinite loop, prog...
should modify some external state - for instance, the filesystem.