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Run Shell Script on Selected Text on Mac

· 2 min read
gityeop
gityeop
Creator of OnText

OnText can run a shell script with the text you selected in the current Mac app. This is useful when a small command is faster than copying text into Terminal, running a script, then pasting the result back.

The workflow is: select text, press F2, then trigger your shell script action.

Basic Shell Action​

Create a Shell Script action in OnText and use {text} where the selected text should be inserted:

echo '{text}' | tr '[:lower:]' '[:upper:]' | pbcopy

This copies an uppercase version of the selected text to the clipboard.

Replace Text After Processing​

Use OnText placeholders when you want to process text and paste it back:

echo '{text}' | tr '[:lower:]' '[:upper:]' | pbcopy && {paste}

The command transforms the selection, writes it to the clipboard, then uses {paste} to paste the result.

Safer Placeholder Options​

OnText supports multiple placeholders for different cases:

  • {text} for fast selected text capture.
  • {textWithCopy} when an app needs copy-based selected text capture.
  • {clipboard} for the current clipboard.
  • {prompt} to ask for extra input before running the action.
  • {date}, {time}, and {datetime} for timestamped workflows.

Read the placeholders guide before building scripts that modify text in place.

Good Use Cases​

Shell script actions are useful for:

  • Formatting identifiers such as snake_case or CONSTANT_CASE.
  • Cleaning whitespace or line breaks.
  • Sending selected text to a local command-line tool.
  • Building small clipboard transformations.
  • Combining selected text with prompts or dates.

For more examples, see Shell Scripts and Custom Actions.