Bash Exit Codes

 Bash Exit Codes

The exit code is a number between 0 and 255. This is the value that returns to the parent process after the completion of a child's process. In other words, it denotes the exit status of the last command of our function.

The exit code value returns based on whether a command or program will successfully execute or not.

• Success – A zero (0) value represents success.
• failure – A non-zero exit code represents failure.

Example

Write a program to write some content in /tmp/tesfile.txt file and check command is executed successfully or not.

Shell

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#!/bin/bash   echo "hi" > /tmp/tesfile.txt   if [ $? -eq 0 ]; then   echo "Hurrey. it works" else   echo "Sorry, can't write /tmp/tesfile.txt" fi

Another Example

Write a program to search for a string in a file and check if the string is present or not.

Shell

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#!/bin/bash   STRING="test"   if grep ${STRING} /etc/passwd then   echo "Yeah! string found" else   echo "Ooooh, no matching string found" fi

This program will search if the string “test” present in /etc/passwd file.