Printing the return code
To get the status of the last command executed in bash, you can check the value of $?.
$?- If the return code is 0 (zero), the last command execution was successful
- All other exit codes are listed in the table below.
List of all bash return codes
Here is a list of all Bash reserved exit codes, reference: https://tldp.org/LDP/abs/html/exitcodes.html
Examples
Bash getting the last command return code
Let us explore further with some examples. For this experiment, we have one file in a folder as shown below:
dev@codetryout:~/sample-git$ ls -ltr
total 0
-rw-rw-r-- 1 dev dev 0 Apr 27 2020 file1
dev@codetryout:~/sample-git$To get a 0 return code, (success) checking whether a file exists
dev@codetryout:~/sample-git$ test -f file1
dev@codetryout:~/sample-git$
dev@codetryout:~/sample-git$ echo $?
0
dev@codetryout:~/sample-git$To get a non-zero return code, checking with a non-existing file
dev@codetryout:~/sample-git$ test -f file2
dev@codetryout:~/sample-git$
dev@codetryout:~/sample-git$ echo $?
1
dev@codetryout:~/sample-git$ We have used test commands for the demo, any commands will have an exit code like this.
Another example, checking the return code for the command, date
dev@codetryout:~/sample-git$ date
Wednesday 06 Jan 2020 01:01:13 PM IST
dev@codetryout:~/sample-git$
dev@codetryout:~/sample-git$ echo $?
0
dev@codetryout:~/sample-git$ That said, any commands executed in a Linux system will have a return code and that can be printed using $?