Ssh Remote Command Exit Code

SSH Remote command exit code

The reason your ssh is always returning 0 is because the final echo command is always succeeding! If you want to get the return code from scan, either remove the echo or assign it to a variable and use exit. On my system:

$ ssh host 'false'
$ echo $?
1
$ ssh host 'false; echo $?'
1
$ echo $?
0
$ ssh host 'false; ret=$?; echo $ret; exit $ret'
1
$ echo $?
1

SSH Remote command exit code always get 0

I should use single quotation marks to double quotation marks.
echo $? will become "0", if I use double quotation marks to execution ssh command.

ssh 127.0.0.1 'ssh_test/test.sh; echo $?'

bash - Capture exit code from remote ssh command

The script appears to be running under set -e, which means when the ssh connection fails, the script exits immediately.

SSH capture exit code of remote ssh commands

Okay. It seems that this was a mistake on my end, and everything is working correctly. I wasn't calling one of the commands correctly:

php "$RELEASE_DIR" artisan migrate --no-interaction --force

This fixes it:

php "$RELEASE_DIR/artisan" migrate --no-interaction --force

Get return code from command run on ssh tunnel

This is not related to SSH, but to how bash handles the exit status in pipelines. From the bash manual page:

The return status of a pipeline is the exit status of the last command, unless the pipefail option is enabled. If pipefail is enabled, the pipeline's return status is the value of the last (rightmost) command to exit with a non-zero status, or zero if all commands exit successfully. If the reserved word ! precedes a pipeline, the exit status of that pipeline is the logical negation of the exit status as described above. The shell waits for all commands in the pipeline to terminate before returning a value.

If you want to check that there was an error in the pipeline due to any of the commands involved, just set the pipefail option:

set -o pipefail
your_pipeline_here
echo $? # Prints non-zero if something went wrong

It is not possible to actually send the exit status to the next command in the pipeline (in your case, ssh) without additional steps. If you really want to do that, the command will have to be split like this:

res="$(/home/mycode.sh '20'${ODATE} 1)"
if (( $? == 0 )); then
    echo -n "$res" | ssh -L 5432:localhost:5432 myuser@myremotehost cat
else
    # You can do anything with the exit status here - even pass it on as an argument to the remote command
    echo "mycode.sh failed" >&2
fi

You may want to save the output of mycode.sh to a temporary file instead of the $res variable if it's too large.

How to separate remote ssh exit codes by groups?

From man ssh:

ssh exits with the exit status of the remote command or with 255 if an error occurred.

So there is only one special exit code. You don't have to keep a list of exit codes for things like "SSH port is closed", "the host is down", and so on.

If your command never exits with 255 or you don't care about that specific code you can use

ssh root@server 'some command'
sshstatus=$?
if (( status == 255 )); then
    echo "connection error"
elif (( status != 0 )); then
    echo "command error"
fi

If you need to catch all exit codes (even 255) from your command, or you really, really, really, don't want to manually specify any special exit codes, then you have to print the command's exit code on the server side and extract it on the client side:

cmdstatusfile=$(mktemp)
ssh root@server 'some command; status=$?; wait; printf %3d $status' |
    tee >(tail -c3 "$cmdstatusfile") | head -c-3
sshstatus=$?
cmdstatus=$(< "$cmdstatusfile")
rm "$cmdstatusfile"
if (( sshstatus != 0 )); then
    echo "connection error"
elif (( cmdstatus != 0 )); then
    echo "command error"
fi

If you normally pipe ssh ... into something you can still do so. Simply add your pipe after head ....

This approach assumes that some command always exits normally. With set -e or exit inside some command the exit code wouldn't be printed at the end. In those cases you could print the exit code inside a trap.

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