Rep

Command-line find and replace with a text editor

rep is a command-line utility that takes grep-formatted lines (e.g., from ripgrep) and applies a find and replace on the matches. It does basic find and replace right on the command line, or the grep output can be edited manually with a text editor, and then the changes can be applied.

This means you can use all the features of a text editor including multiple cursors, find and replace, sorting, etc., and then apply the changes. For example:

1. rg -n "(BananaStand|banana[_-]stand)" > /tmp/out.txt
2. Edit /tmp/out.txt in a text editor turning banana stand into lemonade stand
3. rep < /tmp/out.txt to review the changes as a diff
4. rep -w < /tmp/out.txt to write the changes

Simple Example

rep can also perform a find and replace from grep output without using a text editor.

Output a diff to standard output replacing foo with bar:

grep -n foo *` | rep foo bar

Add the -w flag to write the changes to the files in place:

grep -n foo *` | rep foo bar -w

The -n (--line-number) option is required so that grep outputs the line number for each match.

Writing by Editing Standard Input

Like wgrep for Emacs, writing to files can also be accomplished by editing the contents of the grep output itself (and omitting the find and replace arguments).

This means for example a workflow like this will work:

1. grep -n foo * > tmp: Save the grep matches to a file named tmp.
2. sed -i '' s/foo/bar/g tmp: Replace foo with bar in the tmp file.
3. rep < tmp: Display a diff of replacing foo with bar for each grep match.
4. rep -w < tmp: Write the changes to replace foo with bar for each grep match.

Flow

The flow rep uses when making a change looks like this:

1. The input line is broken up into these parts: <file-path>:<line-number>:[<column-number>:]<line-content>.
2. The substitution (e.g., the first and second [find and replace] arguments) are applied to the <line-contents>.
3. The result is written to the <file-path>.

These means editing standard input first, and then also applying a find and replace via rep, will also work (e.g., rep bar baz < tmp).

Installation

rep is available via cargo:

cargo install rep-grep

Configuration

The default pager is less, the REP_PAGER environment variable can be used to override the pager (e.g., export REP_PAGER=delta in Bash).

Help

rep -h (or rep --help, --help provides slightly longer explanations of some options) will list help for all the command-line flags.

Acknowledgements

• rep was inspired by wgrep for Emacs, which allows editing grep results in an Emacs buffer and then writing those changes to the source files.
• Much of the functionality, and the overall structure of the source code, was borrowed sd. rep began as a fork of sd.
• The code for specifying a custom pager for rep was borrowed from delta.