In some strange situations it would be more helpful for us to find the previously executed command’s status(success or not). We can figure it out by using the following command;

# echo $?

Output:

0 : The '0' represents, successfully executed command status. :-)
Any other digit : represents, the previously executed command was failed. :-(

Example:

----
[[email protected] ~]# gdgmd
bash: gdgmd: command not found
[[email protected] ~]# echo $?
127
----
[[email protected] ~]# man ls
[[email protected] ~]# echo $?
0
----

Related Links:
echo $SHELL