How to handle ALL error messages, even when a command does not work?

Question

I am a bit rusty on my bash shell scripting. I have created the following script:

#!/bin/bash

display_usage() {
        echo -e "\nUsage: This script must be run with both a valid source and a target client name."
        echo -e "Example: ./createClientRolesRespChart <source client name> <target client name>\n"
        }

mv $1 $2

# If less than two arguments supplied, display usage
if [  $# -le 1 ]; then
        display_usage
        exit 1
fi

if [ $? -eq 0 ]; then
   echo "Created new response chart for the $2 client."
   exit 0
else
    echo "[Error] Move (mv) command failed. Please check parameters are correct."
    exit 1
fi

The script works, BUT if I enter a wrong filename, the command fails, buy it still prints the success message. Any hints. Should be an easy thing. I just forget :(

bash-3.2$ ./createClientRolesRespChart foo bar
mv: rename foo to bar: No such file or directory
Created new response chart for the bar client.

Answer 1

$? only says whether the last command succeeded. In your case, you're doing an mv , which is failing, then looking at the argument count, then looking at $? , which will now contain the result of the argument count check, and not of the mv . To fix it, switch the argument count check and the mv .