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Liam's Reference

Bash Parameter Expansion

Substrings

Section titled “Substrings”
Terminal window
str="Hello, world! I am an example, used below."

Remove from end

Section titled “Remove from end”
Terminal window
# Hello, world! I am an example, used below.
echo "${str%,*}"
# Hello, world! I am an example

Remove from end (greedy)

Section titled “Remove from end (greedy)”
Terminal window
# Hello, world! I am an example, used below.
echo "${str%%,*}"
# Hello

Remove from start

Section titled “Remove from start”
Terminal window
# Hello, world! I am an example, used below.
echo "${str#*, }"
# world! I am an example, used below.

Remove from start (greedy)

Section titled “Remove from start (greedy)”
Terminal window
# Hello, world! I am an example, used below.
echo "${str##*, }"
# used below.

Replace first occurrence

Section titled “Replace first occurrence”
Terminal window
# Hello, world! I am an example, used below.
echo "${str/,/_}"
# Hello_ world! I am an example, used below.

Replace all occurrences

Section titled “Replace all occurrences”
Terminal window
# Hello, world! I am an example, used below.
echo "${str//,/_}"
# Hello_ world! I am an example_ used below.