Bash - trim string

In this article, we would like to show you how to trim string using Bash.

Quick solution:

echo '   text   ' | awk 'match($0,/^\s*(.*)\s*$/,g){print g[1]}'

Note:

On the internet you can also find a solution using xargs, however it was not created to trim text and may damage your code.

Practical example

In this example, we create a reusable function that uses awk to trim the string that we pass as the first argument ($1).

#!/bin/bash

function trim_string() {
    echo "$1" | awk 'match($0,/^\s*(.*)\s*$/,g){print g[1]}'
}


# Usage example 1:

trim_string '   text   '

Alternative solution

In this example, we present a script that uses Bash wildcards to trim whitespace characters from the variable string.

script.sh file:

#!/bin/bash

variable="     text  "

# removes spaces from the beginning
variable="${variable#"${variable%%[![:space:]]*}"}"

# removes spaces from the end
variable="${variable%"${variable##*[![:space:]]}"}"   

echo "$variable"

Run in command line:

./script.sh

Output:

text