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bash EXIT traps to ensure resource cleanup
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#!/bin/bash | |
# Call like `./traps.bash 0` and you should see: | |
# outside | |
# level 1 | |
# level 2 | |
# level 2 trap | |
# This won't run on error | |
# level 1 trap | |
# Nor with this on error | |
# | |
# Call like `./traps.bash 1` and you should see: | |
# outside | |
# level 1 | |
# level 2 | |
# level 2 trap | |
# level 1 trap | |
level1_cleanup() { | |
echo "level 1 trap" | |
} | |
# You can also call a function that also sets its own trap | |
levelX() { | |
echo level $1 | |
trap "echo level $1 trap" EXIT | |
} | |
main() { | |
# we are concerned about failures and need to exit | |
# early, so we set -e to bail out if a problem | |
set -e | |
# some code on the outside | |
echo "outside" | |
# we use subshells so we can trap the exit from | |
# each subshell "level" and perform a cleanup action | |
( | |
# some command that makes something you need to cleanup | |
echo "level 1" | |
trap level1_cleanup EXIT | |
# code using resource | |
( | |
# another command that makes something you need to cleanup | |
levelX 2 | |
# code using resource | |
# ... | |
# some command that errors and retuns an | |
# exit code of whatever is passed in | |
exit $1 | |
) | |
# back out to level 1 | |
echo "This won't run on error" | |
) | |
# more code on the outside | |
echo "Nor with this on error" | |
} | |
main $@ |
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See more about exit traps here: http://redsymbol.net/articles/bash-exit-traps/.