How to trim string in bash

Sometimes it requires to remove characters from the starting and end of the string data which is called trimming. There is a built-in function named trim() for trimming in many standard programming languages. Bash has no built-in function to trim string data. But many options are available in bash to remove unwanted characters from string data, such as parameter expansion, sed, awk, xargs, etc. How you can trim string in bash is shown in this tutorial by using different examples.

Example-1: Trim string data using parameter expansion

Space or any character can be trimmed easily from the string data by using bash parameter expansion. The following commands show the uses of parameter expansion for removing space from the starting and end of the string.

Example-2: Trim string data using `sed` command

`sed` command is another option to remove leading and trailing space or character from the string data. The following commands will remove the spaces from the variable, $myVar using `sed` command.

Use sed ‘s/^ *//g’, to remove the leading white spaces.
There is another way to remove whitespaces using `sed` command. The following commands removed the spaces from the variable, $Var by using `sed` command and [[:space:]].

Example-3: Trim string data using `awk` command

`awk` command is another way to trim the string value. The following commands uses `awk` command to remove spaces from the starting and ending of the variable, $Input_text.

Example-4: Trim string data using xargs command

`xargs` is another simple command to trim string data.

Conclusion:

This tutorial shows the different ways to trim string data. The string data needs to trim for various reasons. For example, it is better to remove extra spaces from the starting and end of the data before inserting into the database or compare with other value. This tutorial will help the new users to learn trimming options in bash.