Regular Expression in Bash

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Fish Shell is preferred to Bash/Zsh. The following content is for Bash/Zsh only.

It is suggested that you use Python script instead of Shell script as much as possible. If you do have to stick with Shell script, you can use =~ for regular expression matching in Bash. This make Bash syntax extremely flexible and powerful. For example, you can match multiple strings using regular expression.

if [[ value =~ ^(v1|v2|v3)$ ]]; then
    ...
fi