GOTO is frowned upon. Bash simply removed goto. this causes problems, particularly if you do have a need to skip to a particular section of code. Web search turned up various people recommending the use of functions instead. This still doesn't solve the problem of non-local resumption.
Closest I found was Bob Copeland's approach: http://bobcopeland.com/blog/2012/10/goto-in-bash/
It's an interesting use of sed to much up the script up to the "label" and then executing the script. Very Neat trick. I wanted something simpler within Bash itself.
My problem is pretty much the same as Bob indicates on his web-page: i have a script that must process things in several steps, each of which is time consuming and can fail. Re-running prior steps is prohibitive, so I need some mechanism to resume from where the script last failed (or close to it).
So here's what I came up with:
#!/bin/bash
function usage() {
echo "$0 [step]"
}
label=$1;
if [ -z "$label" ]; then label="step1"; fi
# do all common setup here. This stuff will be done each time the script is run
while true; do
echo processing step [$label]; # to give a hint about where to restart from
case "$label" in
"step1")
# add processing for step1 here
label="step2"
;;
"step2")
# add processing for step2 here
label="step3"
;;
"step3")
# add processing for step3 here
label="end"
;;
"end") echo done; break;;
*)
usage
exit
;;
esac
done
Here's how it runs:
# /tmp/test_goto.sh
processing step [step1]
processing step [step2]
processing step [step3]
processing step [end]
done
# /tmp/test_goto.sh step2
processing step [step2]
processing step [step3]
processing step [end]
done
