[SOLVED] Make shell script exit as soon as a command in it returns an error?

[jasper.davidson]

I would like to make my shell script so that if any of the commands in it return an error, the script immmediately exits without executing the rest of the commands. What might be the best way of doing this? One way that seems to work is:
#!/bin/bash
cmd1 || exit 1
cmd2 || exit 1
cmd3 || exit 1
etc.
In other words, putting "|| exit 1" at the end of each executed command. Is there a better way I hope? Thanks in advance.

[dwhitney67]

Do something like this:

#!/bin/sh

set -e

...


If you are using bash script, then change the "sh" to "bash".

[jasper.davidson]

Thank you very much, dwhitney67, that's exactly what I was looking for. I knew there had to be a better way than putting "|| exit 1" at the end of each command. :)

[jasper.davidson]

One more question though if you have time; is there any way to exclude a single command from causing the script to exit when I use "set -e" at the beginning? In other words, there are just a few commands in my script that it doesn't matter if they return an error, and I don't want the entire script to terminate for those few commands. Is there possibly some way around that? Thanks again.

EDIT: I think I found a workaround, although it probably isn't the best solution again:

#!/bin/bash
set -e
cmd1
cmd2
#exclude next command from causing script to terminate:
set +e; cmd3; set -e
#continue:
cmd4

[dwhitney67]

If you only have a few cases where the failure of a command is not important, then I would toggle the "e" option as you have done.

Or you could do something cheesy like:

#!/bin/bash

function execCmd()
{
eval "$1"

status=$?

if [[ $status -ne 0 && "$2" != "ignore" ]]
then
echo "stopping..."
exit $status
fi
}


# Main

execCmd "ls"
echo "continuing..."
echo

execCmd "touch /foo" "ignore" # ignore error for this command
echo "continuing..."
echo

execCmd "touch /foo" # terminate script if this fails

# should not reach here
echo "done"

[mssever]

One more question though if you have time; is there any way to exclude a single command from causing the script to exit when I use "set -e" at the beginning? In other words, there are just a few commands in my script that it doesn't matter if they return an error, and I don't want the entire script to terminate for those few commands. Is there possibly some way around that? Thanks again.

EDIT: I think I found a workaround, although it probably isn't the best solution again:

#!/bin/bash
set -e
cmd1
cmd2
#exclude next command from causing script to terminate:
set +e; cmd3; set -e
#continue:
cmd4

The easiest way to ignore errors from one single command is to do somecommand || true

[dwhitney67]

The easiest way to ignore errors from one single command is to do somecommand || true
Why didn't I think of that??!

That does make it easier.

[jasper.davidson]

That's a great way to exclude a command from causing the script to terminate, mssever. Thanks for the help. :)