cat.js

Concatenates and prints files on the standard output like the cat command.

There are multi-platform file-system commands compatible with cat from UN*X implemented for Node.js in JavaScript, like cat, but they have a different interface and a different behaviour than the cat command. Instead of reusing the knowledge of the cat command, you would have to learn their new interface. This project aims to provide the well-known interface of the cat command.

This package offers only command-line interface, because programmatic interface is provided by methods from node:fs. See also other commands compatible with their counterparts from UN*X - rm.js, cp.js, ln.js, mkdir.js and mv.js.

Synopsis

The following scripts from package.json won't work on Windows:

rm -rf dist
mkdir -p dist
cat src/umd-prolog.txt src/code.js src/umd-epilog.txt > dist/index.umd.js
cp src/index.d.ts dist
mv LICENSE doc
ln -s ../src src

Replace them with the following ones, which run on any operating system which is supported by Node.js:

rm-j -rf dist
mkdir-j -p dist
cat-j src/umd-prolog.txt src/code.js src/umd-epilog.txt > dist/index.umd.js
cp-j src/index.d.ts dist
mv-j LICENSE doc
ln-j -s ../src src

Notice that the only difference is the suffix .js behind the command names.

Installation

This module can be installed in your project using NPM, PNPM or Yarn. Make sure, that you use Node.js version 16 or newer.

$ npm i -D @unixcompat/cat.js
$ pnpm i -D @unixcompat/cat.js
$ yarn add -D @unixcompat/cat.js

Command-line Interface

See also man cat for the original POSIX documentation or for the extended Linux implementation.

Usage: cat-j [-AbeElnstTuv] [--] file...

Options:
  -A|--show-all          equivalent to -vET
  -b|--number-nonblank   number the non-blank output lines, starting at 1
  -e|--show-np-and-ends  equivalent to -vE
  -E|--show-ends         display a dollar sign ("$") at the end of each line
  -l|--lock              set an exclusive advisory lock on standard output;
                         if the output file is already locked, this command
                         will block until the lock is acquired
  -n|--number            number all output lines, starting at 1
  -s|--squeeze-blank     squeeze adjacent empty lines to a single one
  -t|--show-np-and-tabs  equivalent to -vT
  -T|--show-tabs         display TAB characters as "^I"
  -u|--unbuffering       ignored (originally disable output buffering)
  -v|--show-nonprinting  display non-printing characters so they are visible;
                         control characters as "^X", DEL character as "^?",
                         non-ASCII characters as "M-" and the ASCII character
  -V|--version           print version number
  -h|--help              print usage instructions

  If file is a single dash ("-") or absent, the standard input will be used.

Examples:
  $ cat-j a
  $ cat-j -s /tmp/a /tmp/b > /tmp/c

Differences

The following options from the POSIX version are not supported, but they are accepted and ignored:

-u    write bytes from the input file to the standard output without delay
      as each is read

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using npm test.

License

Copyright (c) 2023 Ferdinand Prantl

Licensed under the MIT license.