Bash ignoring error for a particular command

Question

I am using following options

set -o pipefail
set -e

In bash script to stop execution on error. I have ~100 lines of script executing and I don't want to check return code of every line in the script.

But for one particular command, I want to ignore the error. How can I do that?

Answer 1

The solution:

particular_script || true

Example:

$ cat /tmp/1.sh
particular_script()
{
    false
}

set -e

echo one
particular_script || true
echo two
particular_script
echo three

$ bash /tmp/1.sh
one
two

three will be never printed.

Also, I want to add that when pipefail is on, it is enough for shell to think that the entire pipe has non-zero exit code when one of commands in the pipe has non-zero exit code (with pipefail off it must the last one).

$ set -o pipefail
$ false | true ; echo $?
1
$ set +o pipefail
$ false | true ; echo $?
0

Answer 2

Just add || true after the command where you want to ignore the error.

Answer 3

Don't stop and also save exit status

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:

set -e
EXIT_CODE=0
command || EXIT_CODE=$?
echo $EXIT_CODE

Answer 4

More concisely:

! particular_script

From the POSIX specification regarding set -e (emphasis mine):

When this option is on, if a simple command fails for any of the reasons listed in Consequences of Shell Errors or returns an exit status value >0, and is not part of the compound list following a while, until, or if keyword, and is not a part of an AND or OR list, and is not a pipeline preceded by the ! reserved word, then the shell shall immediately exit.

Answer 5

Instead of "returning true", you can also use the "noop" or null utility (as referred in the POSIX specs) : and just "do nothing". You'll save a few letters. :)

#!/usr/bin/env bash
set -e
man nonexistentghing || :
echo "It's ok.."

Answer 6

If you want to prevent your script failing and collect the return code:

command () {
    return 1  # or 0 for success
}

set -e

command && returncode=$? || returncode=$?
echo $returncode

returncode is collected no matter whether command succeeds or fails.

Answer 7

output=$(*command* 2>&1) && exit_status=$? || exit_status=$?
echo $output
echo $exit_status

Example of using this to create a log file

log_event(){
timestamp=$(date '+%D %T') #mm/dd/yy HH:MM:SS
echo -e "($timestamp) $event" >> "$log_file"
}

output=$(*command* 2>&1) && exit_status=$? || exit_status=$?

if [ "$exit_status" = 0 ]
    then
        event="$output"
        log_event
    else
        event="ERROR $output"
        log_event
fi

Answer 8

I have been using the snippet below when working with CLI tools and I want to know if some resource exist or not, but I don't care about the output.

if [ -z "$(cat no_exist 2>&1 >/dev/null)" ]; then
    echo "none exist actually exist!"
fi

Answer 9

No solutions worked for me from here, so I found another one:

set +e
find "./csharp/Platform.$REPOSITORY_NAME/obj" -type f -iname "*.cs" -delete
find "./csharp/Platform.$REPOSITORY_NAME.Tests/obj" -type f -iname "*.cs" -delete
set -e

This is useful for CI & CD. This way the error messages are printed but the whole script continues to execute.

Answer 10

I kind of like this solution :

: `particular_script`

The command/script between the back ticks is executed and its output is fed to the command ":" (which is the equivalent of "true")

$ false
$ echo $?
1
$ : `false`
$ echo $?
0

edit: Fixed ugly typo

Answer 11

while || true is preferred one, but you can also do

var=$(echo $(exit 1)) # it shouldn't fail

Answer 12

Thanks for the simple solution here from above:

<particular_script/command> || true

The following construction could be used for additional actions/troubleshooting of script steps and additional flow control options:

if <particular_script/command>
then
   echo "<particular_script/command> is fine!"
else
   echo "<particular_script/command> failed!"
   #exit 1
fi

We can brake the further actions and exit 1 if required.