How to trim whitespace from a Bash variable?

How to Trim Whitespace from a Bash Variable? :scissors: :shell:

Are you tired of dealing with annoying whitespace in your Bash variables? :weary: Don't worry, I've got you covered! In this blog post, I'll show you some easy solutions to trim whitespace from your Bash variables, so you can keep your code clean and elegant. :sparkles:

The Problem :thinking:

Let's take a look at the code snippet you provided:

var=`hg st -R "$path"`
if [ -n "$var" ]; then
    echo $var
fi

The issue here is that the hg st command always adds a newline character to the output, which means the $var variable will never be empty, causing the conditional code to always execute. :no_entry_sign:

Solution 1: Using Parameter Expansion :muscle:

One simple solution is to use parameter expansion to remove leading and trailing whitespace from the variable. :raised_hands: Here's an example:

var=$(hg st -R "$path")
var="${var#"${var%%[![:space:]]*}"}"
var="${var%"${var##*[![:space:]]}"}"

In this solution, we use ${var#"${var%%[![:space:]]*}"} to remove leading whitespace, and ${var%"${var##*[![:space:]]}"} to remove trailing whitespace. :arrow_forward: Easy, right?

Solution 2: Using sed :fish:

If you prefer using sed, you can achieve the same result with a simple one-liner. :calling: Here's how:

var=$(hg st -R "$path" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')

In this solution, the sed command removes leading whitespace with s/^[[:space:]]*//, and trailing whitespace with s/[[:space:]]*$//. :wave: Problem solved!

Solution 3: Using awk :mag_right:

Lastly, for those who are fans of awk, you can also leverage its power to trim whitespace from your variable. :zap: Take a look:

var=$(hg st -R "$path" | awk '{$1=$1};1')

In this solution, we use the awk command with the '{$1=$1};1' pattern, which forces awk to reformat the input and remove leading and trailing whitespace. :white_check_mark: Cool, right?

Conclusion and Call-to-Action :raised_hands: :keyboard:

Trimming whitespace from a Bash variable doesn't have to be a headache. :relieved: With the solutions provided above, you can easily clean up your variables and make your code more readable. Choose the solution that suits your preference and start enjoying cleaner code today!

Do you have any other tips or tricks for dealing with whitespace in Bash variables? :bulb: Share them in the comments below and let's have a discussion! :speech_balloon:

Happy coding! :computer: