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What happens if a command fails in Linux?
This means that the usual if and && / || approaches won’t work for those particular commands. For instance, on Linux GNU file still exits with 0 if it received a non-existing file as argument and find couldn’t locate the file user specified.
What causes a bash script to exit without an exit code?
Putting this at the top of a bash script will cause the script to exit if any commands return a non-zero exit code. We can get a little fancier if we use DEBUG and EXIT traps to execute custom commands before each line of the script is run and before the script exits, respectively.
How to handle errors in a bash script?
Inspired by the ideas presented here, I have developed a readable and convenient way to handle errors in bash scripts in my bash boilerplate project. By simply sourcing the library, you get the following out of the box (i.e. it will halt execution on any error, as if using set -e thanks to a trap on ERR and some bash-fu ):
How to report failure in a shell script?
A single failure in a shell script automatically updates a GUI; something like this: (Note: This can also be used in conjunction with trap on error, to report where the failure occurred, rather than just aborting without giving a clue as to the reason.) Here is a simple example of a script: fail.sh.
How to avoid corruption on power off in Linux embedded?
We all know that the OS (linux or windows or whatever) *should* be gracefully powered down with a shutdown procedure (shutdown command in Linux). We must avoid cutting the power abruptly. If this is possible for desktop systems, IMHO it’s impossible to achieve in embedded systems.
How to conditionally do something if a command failed?
How to conditionally do something if a command succeeded or failed. That’s exactly what bash’s if statement does: if command ; then echo “Command succeeded” else echo “Command failed” fi. Adding information from comments: you don’t need to use the [ ] syntax in this case. [ is itself a command, very nearly equivalent to test.
When to ignore error code of failed command?
Just in case if you want your script not to stop if a particular command fails and you also want to save error code of failed command: