bash errors

"Errors" a comic by Julia Evans @bork.

Panel 1: by default, bash will continue after errors. Bash says "oh, was that an error? who cares, let's keep running!!!" Programmer with a blank face says "uh is that really the best choice?"

Panel 2: set -e stops the script on errors. set -e
unzip fle.zip <-- typo! script stops here
Programmer with a smiley face says "this makes your scripts WAY more predictable."

Panel 3: by default, unset variables don't error.
rm -r "$HOME/$SOMEPTH"
Bash says "$SOMEPTH doesn't exist? no problem, i'll just use an empty string!" Programmer with a frowny face says "OH NOOOO"

Panel 4: set -u stops the script on unset variables.
set -u
echo $UNSET <-- oops!
Bash says "I've never heard of that variable! STOP EVERYTHING!!!"

Panel 5: by default, a command failing doesn't fail the whole pipeline.
curl 404.com | grep 'panda'
Bash says "curl failed but grep succeeded so it's fine! success!"

Panel 6: set -o pipefail prevents this
Programmer with smiley face says "all of these are why I like to put set -euo pipefail at the beginning of all my scripts!