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## subst - commandline tool to replace file contents or file names

> [!CAUTION]
> This software is now being maintained on [Codeberg](https://codeberg.org/scip/subst/).


This script can be used to replace something in a file or filename by using perl
regular expressions. It can also be used to rename files based on regexes.

## Usage

    Usage: subst  [-M <perl module>] [-t]  -r 's/old/new/<flags>' [ -r '...', ...] [<file> ...     | /regex/]
           subst  [-M <perl module>] [-tR] -m 's/old/new/<flags>' [ -m '...', ...] [<file|dir> ... | /regex/]
    
    Options:
     -r        replace contents of file(s)
     -m        rename file(s)
     -R        recursive (only used in conjunction with -m)
     -M        load additional perl module to enhance /e functionality.
     -t        test mode, do not overwrite file(s)
    
    Samples:
     - replace "tom" with "mac" in all *.txt files:
       subst -r 's/tom/mac/g' *.txt
    
     - rename all jpg files containing whitespaces:
       subst -m 's/ /_/g' '/.jpg/'
    
     - decode base64 encoded contents
       subst -M MIME::Base64 -r 's/([a-zA-Z0-9]*)$/decode_base64($1)/gem' somefile
    
     - turn every uri into a link
       subst -M "Regexp::Common qw /URI/" -r 's#($RE{URI}{HTTP})#<a href="$a">link</a>#g' somefile
    
    If <file> is -, STDIN will be used as input file, results will be printed
    to STDOUT. -t does not apply for STDIN input.
    
    Substitution regex must be perlish. See 'perldoc perlre' for details.

## Samples

replace "tom" with "mac" in all *.txt files:

    subst -r 's/tom/mac/g' *.txt

rename all jpg files containing whitespaces:

    subst -m 's/ /_/g' '/.jpg/'

decode base64 encoded contents

    subst -M MIME::Base64 -r 's/([a-zA-Z0-9]*)$/decode_base64($1)/gem' somefile

turn every uri into a link

    subst -M "Regexp::Common qw /URI/" -r 's#($RE{URI}{HTTP})#<a href="$a">link</a>#g' somefile

## DEPENDENCIES

`subst` is a perl script and as such needs perl.

## Installation

Copy [subst](subst) to `$HOME/bin/subst`, that's all.
No additional perl modules are required.

## Copyleft and License

Copyright (c) 2002-2025 - T.v. Dein

This software is licensed under the GNU GENERAL PUBLIC LICENSE version 3.

## Authors

T.v.Dein <tom AT vondein DOT org>

## Project homepage

https://codeberg.org/scip/subst