Insert_after

Inserts a line into a file after a line matching a regular expression. String comparisons are case-insensitive. Works on very large files because it reads the file line by line instead of reading the entire file into memory.

Can be used on the command line or in a Ruby program.

Command-line Installation

$ gem install insert_after

Installation For Use In a Ruby Program

Either add this line to your application’s Gemfile:

gem 'insert_after'

... or add the following to your application’s .gemspec:

spec.add_dependency 'insert_after'

And then execute:

$ bundle

Command-line Usage

# Inserts 'Inserted 1' after the first line containing 'line' into demo/my_file.txt:
$ insert_after line 'Inserted 1' demo/my_file.txt

# Inserts 'Inserted 1' after every line containing 'line' into demo/my_file.txt:
$ insert_after -a line 'Inserted 1' demo/my_file.txt

# Inserts an empty line after the first line containing 'line 1' into demo/my_file.txt:
$ insert_after 'line 1' '' demo/my_file.txt

# Inserts an empty line after every line containing 'line 1' into demo/my_file.txt:
$ insert_after -a 'line 1' '' demo/my_file.txt

# Inserts 'Inserted 2' after the first line starting with 'line 2' into demo/my_file.txt:
$ insert_after '^line 2' 'Inserted 2' demo/my_file.txt

# Inserts 'Inserted 2' after every line starting with 'line 2' into demo/my_file.txt:
$ insert_after -a '^line 2' 'Inserted 2' demo/my_file.txt

# Inserts 'Inserted 3' after the first line containing an 'e' followed by a '2' into demo/my_file.txt:
$ insert_after 'e.*2' 'Inserted 3' demo/my_file.txt

# Inserts 'Inserted 3' after every line containing an 'e' followed by a '2' into demo/my_file.txt:
$ insert_after -a 'e.*2' 'Inserted 3' demo/my_file.txt

Ruby Program Usage

The demo/demo.rb program is an example of how to use insert_after in a Ruby program:

require 'insert_after'

InsertAfer.insert_after  'line 2', 'New line',               'my_file.txt'
InsertAfter.insert_after 'line',   'Another line from Ruby', 'my_file.txt', all: true

Development

After checking out this git repository, install dependencies by typing:

$ bin/setup

You should do the above before running Visual Studio Code.

Run the Tests

$ bundle exec rspec

Interactive Session

The following will allow you to experiment:

$ bin/console

Local Installation

To install this gem onto your local machine, type:

$ bundle exec rake install

To Release A New Version

To create a git tag for the new version, push git commits and tags, and push the new version of the gem to https://rubygems.org, type:

$ bundle exec rake release

Contributing

Bug reports and pull requests are welcome at https://github.com/mslinn/insert_after.

License

The gem is available as open source under the terms of the MIT License.