Extracting substrings

Fish Shell:
Extracting substrings

How to:

In Fish, you use string command to manipulate strings. Here’s how:

Grab from start:

set my_string "Fish Shell is fun!"
echo $my_string | string sub -l 4 # Outputs 'Fish'

Snip from end:

set my_string "Fish Shell is fun!"
echo $my_string | string sub -s -4 # Outputs 'fun!'

Specific range:

set my_string "Fish Shell is fun!"
echo $my_string | string sub -s 6 -l 5 # Outputs 'Shell'

Deep Dive

In the old days, we’d slice and dice strings in Fish using external tools like cut, awk, or sed. Now, string is our go-to built-in function introduced in Fish 2.3.0. It’s faster, more readable, and integrates seamlessly with our scripts.

string sub isn’t your only option. Other string functions can split strings, replace parts, or join them. This focuses on minimal resource use and ease of understanding.

Regarding implementation, when you extract substrings, Fish reads the string and outputs just the part you’ve specified, all while respecting character encoding and avoiding common bugs in substring extraction, like splitting a character in half.

Fish Shell:Extracting substrings