ShellJS is a portable (Windows/Linux/OS X) implementation of Unix shell commands on top of the Node.js API. It provides the ability to script shell commands within JavaScript files and is used for tasks such as file manipulation, program execution, and script automation.
File Operations
ShellJS can perform file operations such as copying, removing, and moving files or directories.
const shell = require('shelljs');
shell.cp('-R', 'source_folder', 'destination_folder');
shell.rm('-rf', 'folder_to_delete');
shell.mv('old_file.txt', 'new_file.txt');Executing Shell Commands
It can execute any shell command and capture its output.
const shell = require('shelljs');
let output = shell.exec('echo hello world', {silent:true}).stdout;
console.log(output);Searching and Modifying Files
ShellJS can search for files that match a pattern and perform text replacement within files.
const shell = require('shelljs');
let files = shell.find('.').filter(file => file.match(/\.js$/));
shell.sed('-i', 'original_text', 'new_text', 'file.js');Environment Variables
It allows manipulation of environment variables within a script.
const shell = require('shelljs');
shell.env['VAR_NAME'] = 'value';
console.log(shell.env['VAR_NAME']);Directory Navigation
ShellJS can change the current working directory and get the present working directory.
const shell = require('shelljs');
shell.cd('path/to/directory');
console.log(shell.pwd().stdout);This is a core Node.js module that allows you to execute shell commands and is more low-level compared to ShellJS. It does not provide the Unix shell command syntax, requiring more manual setup for cross-platform compatibility.
Execa is a process execution tool that aims to be more feature-rich and have better Windows support than Node.js's child_process. It returns promises and can handle multiple processes simultaneously.
Cross-spawn is a cross-platform solution for spawning child processes with command-line arguments. It normalizes Node.js issues on Windows and is used when you need to spawn processes with command-line arguments that are shell-friendly.
ShellJS is a portable (Windows/Linux/OS X) implementation of Unix shell commands on top of the Node.js API. You can use it to eliminate your shell script's dependency on Unix while still keeping its familiar and powerful commands. You can also install it globally so you can run it from outside Node projects - say goodbye to those gnarly Bash scripts!
The project is unit-tested and battled-tested in projects like:
and many more.
If you have feedback, suggestions, or need help, feel free to post in our issue tracker.
Via npm:
$ npm install [-g] shelljs
If the global option -g is specified, the binary shjs will be installed. This makes it possible to
run ShellJS scripts much like any shell script from the command line, i.e. without requiring a node_modules folder:
$ shjs my_script
require('shelljs/global');
if (!which('git')) {
echo('Sorry, this script requires git');
exit(1);
}
// Copy files to release dir
mkdir('-p', 'out/Release');
cp('-R', 'stuff/*', 'out/Release');
// Replace macros in each .js file
cd('lib');
ls('*.js').forEach(function(file) {
sed('-i', 'BUILD_VERSION', 'v0.1.2', file);
sed('-i', /.*REMOVE_THIS_LINE.*\n/, '', file);
sed('-i', /.*REPLACE_LINE_WITH_MACRO.*\n/, cat('macro.js'), file);
});
cd('..');
// Run external tool synchronously
if (exec('git commit -am "Auto-commit"').code !== 0) {
echo('Error: Git commit failed');
exit(1);
}
CoffeeScript is also supported automatically:
require 'shelljs/global'
if not which 'git'
echo 'Sorry, this script requires git'
exit 1
# Copy files to release dir
mkdir '-p', 'out/Release'
cp '-R', 'stuff/*', 'out/Release'
# Replace macros in each .js file
cd 'lib'
for file in ls '*.js'
sed '-i', 'BUILD_VERSION', 'v0.1.2', file
sed '-i', /.*REMOVE_THIS_LINE.*\n/, '', file
sed '-i', /.*REPLACE_LINE_WITH_MACRO.*\n/, cat('macro.js'), file
cd '..'
# Run external tool synchronously
if (exec 'git commit -am "Auto-commit"').code != 0
echo 'Error: Git commit failed'
exit 1
The example above uses the convenience script shelljs/global to reduce verbosity. If polluting your global namespace is not desirable, simply require shelljs.
Example:
var shell = require('shelljs');
shell.echo('hello world');
A convenience script shelljs/make is also provided to mimic the behavior of a Unix Makefile.
In this case all shell objects are global, and command line arguments will cause the script to
execute only the corresponding function in the global target object. To avoid redundant calls,
target functions are executed only once per script.
Example:
require('shelljs/make');
target.all = function() {
target.bundle();
target.docs();
};
target.bundle = function() {
cd(__dirname);
mkdir('-p', 'build');
cd('src');
cat('*.js').to('../build/output.js');
};
target.docs = function() {
cd(__dirname);
mkdir('-p', 'docs');
var files = ls('src/*.js');
for(var i = 0; i < files.length; i++) {
var text = grep('//@', files[i]); // extract special comments
text = text.replace(/\/\/@/g, ''); // remove comment tags
text.toEnd('docs/my_docs.md');
}
};
To run the target all, call the above script without arguments: $ node make. To run the target docs: $ node make docs.
You can also pass arguments to your targets by using the -- separator. For example, to pass arg1 and arg2 to a target bundle, do $ node make bundle -- arg1 arg2:
require('shelljs/make');
target.bundle = function(argsArray) {
// argsArray = ['arg1', 'arg2']
/* ... */
}
All commands run synchronously, unless otherwise stated.
Changes to directory dir for the duration of the script. Changes to home
directory if no argument is supplied.
Returns the current directory.
Available options:
-R: recursive-A: all files (include files beginning with ., except for . and ..)-d: list directories themselves, not their contents-l: list objects representing each file, each with fields containing ls -l output fields. See
fs.Stats
for more infoExamples:
ls('projs/*.js');
ls('-R', '/users/me', '/tmp');
ls('-R', ['/users/me', '/tmp']); // same as above
ls('-l', 'file.txt'); // { name: 'file.txt', mode: 33188, nlink: 1, ...}
Returns array of files in the given path, or in current directory if no path provided.
Examples:
find('src', 'lib');
find(['src', 'lib']); // same as above
find('.').filter(function(file) { return file.match(/\.js$/); });
Returns array of all files (however deep) in the given paths.
The main difference from ls('-R', path) is that the resulting file names
include the base directories, e.g. lib/resources/file1 instead of just file1.
Available options:
-f: force (default behavior)-n: no-clobber-r, -R: recursiveExamples:
cp('file1', 'dir1');
cp('-Rf', '/tmp/*', '/usr/local/*', '/home/tmp');
cp('-Rf', ['/tmp/*', '/usr/local/*'], '/home/tmp'); // same as above
Copies files. The wildcard * is accepted.
Available options:
-f: force-r, -R: recursiveExamples:
rm('-rf', '/tmp/*');
rm('some_file.txt', 'another_file.txt');
rm(['some_file.txt', 'another_file.txt']); // same as above
Removes files. The wildcard * is accepted.
Available options:
-f: force (default behavior)-n: no-clobberExamples:
mv('-n', 'file', 'dir/');
mv('file1', 'file2', 'dir/');
mv(['file1', 'file2'], 'dir/'); // same as above
Moves files. The wildcard * is accepted.
Available options:
-p: full path (will create intermediate dirs if necessary)Examples:
mkdir('-p', '/tmp/a/b/c/d', '/tmp/e/f/g');
mkdir('-p', ['/tmp/a/b/c/d', '/tmp/e/f/g']); // same as above
Creates directories.
Available expression primaries:
'-b', 'path': true if path is a block device'-c', 'path': true if path is a character device'-d', 'path': true if path is a directory'-e', 'path': true if path exists'-f', 'path': true if path is a regular file'-L', 'path': true if path is a symbolic link'-p', 'path': true if path is a pipe (FIFO)'-S', 'path': true if path is a socketExamples:
if (test('-d', path)) { /* do something with dir */ };
if (!test('-f', path)) continue; // skip if it's a regular file
Evaluates expression using the available primaries and returns corresponding value.
Examples:
var str = cat('file*.txt');
var str = cat('file1', 'file2');
var str = cat(['file1', 'file2']); // same as above
Returns a string containing the given file, or a concatenated string
containing the files if more than one file is given (a new line character is
introduced between each file). Wildcard * accepted.
Examples:
cat('input.txt').to('output.txt');
Analogous to the redirection operator > in Unix, but works with JavaScript strings (such as
those returned by cat, grep, etc). Like Unix redirections, to() will overwrite any existing file!
Examples:
cat('input.txt').toEnd('output.txt');
Analogous to the redirect-and-append operator >> in Unix, but works with JavaScript strings (such as
those returned by cat, grep, etc).
Available options:
-i: Replace contents of 'file' in-place. Note that no backups will be created!Examples:
sed('-i', 'PROGRAM_VERSION', 'v0.1.3', 'source.js');
sed(/.*DELETE_THIS_LINE.*\n/, '', 'source.js');
Reads an input string from files and performs a JavaScript replace() on the input
using the given search regex and replacement string or function. Returns the new string after replacement.
Available options:
-v: Inverse the sense of the regex and print the lines not matching the criteria.Examples:
grep('-v', 'GLOBAL_VARIABLE', '*.js');
grep('GLOBAL_VARIABLE', '*.js');
Reads input string from given files and returns a string containing all lines of the
file that match the given regex_filter. Wildcard * accepted.
Examples:
var nodeExec = which('node');
Searches for command in the system's PATH. On Windows, this uses the
PATHEXT variable to append the extension if it's not already executable.
Returns string containing the absolute path to the command.
Examples:
echo('hello world');
var str = echo('hello world');
Prints string to stdout, and returns string with additional utility methods
like .to().
Available options:
-n: Suppresses the normal change of directory when adding directories to the stack, so that only the stack is manipulated.Arguments:
dir: Makes the current working directory be the top of the stack, and then executes the equivalent of cd dir.+N: Brings the Nth directory (counting from the left of the list printed by dirs, starting with zero) to the top of the list by rotating the stack.-N: Brings the Nth directory (counting from the right of the list printed by dirs, starting with zero) to the top of the list by rotating the stack.Examples:
// process.cwd() === '/usr'
pushd('/etc'); // Returns /etc /usr
pushd('+1'); // Returns /usr /etc
Save the current directory on the top of the directory stack and then cd to dir. With no arguments, pushd exchanges the top two directories. Returns an array of paths in the stack.
Available options:
-n: Suppresses the normal change of directory when removing directories from the stack, so that only the stack is manipulated.Arguments:
+N: Removes the Nth directory (counting from the left of the list printed by dirs), starting with zero.-N: Removes the Nth directory (counting from the right of the list printed by dirs), starting with zero.Examples:
echo(process.cwd()); // '/usr'
pushd('/etc'); // '/etc /usr'
echo(process.cwd()); // '/etc'
popd(); // '/usr'
echo(process.cwd()); // '/usr'
When no arguments are given, popd removes the top directory from the stack and performs a cd to the new top directory. The elements are numbered from 0 starting at the first directory listed with dirs; i.e., popd is equivalent to popd +0. Returns an array of paths in the stack.
Available options:
-c: Clears the directory stack by deleting all of the elements.Arguments:
+N: Displays the Nth directory (counting from the left of the list printed by dirs when invoked without options), starting with zero.-N: Displays the Nth directory (counting from the right of the list printed by dirs when invoked without options), starting with zero.Display the list of currently remembered directories. Returns an array of paths in the stack, or a single path if +N or -N was specified.
See also: pushd, popd
Available options:
-s: symlink-f: forceExamples:
ln('file', 'newlink');
ln('-sf', 'file', 'existing');
Links source to dest. Use -f to force the link, should dest already exist.
Exits the current process with the given exit code.
Object containing environment variables (both getter and setter). Shortcut to process.env.
Available options (all false by default):
async: Asynchronous execution. If a callback is provided, it will be set to
true, regardless of the passed value.silent: Do not echo program output to console.Examples:
var version = exec('node --version', {silent:true}).stdout;
var child = exec('some_long_running_process', {async:true});
child.stdout.on('data', function(data) {
/* ... do something with data ... */
});
exec('some_long_running_process', function(code, stdout, stderr) {
console.log('Exit code:', code);
console.log('Program output:', stdout);
console.log('Program stderr:', stderr);
});
Executes the given command synchronously, unless otherwise specified. When in synchronous
mode returns the object { code:..., stdout:... , stderr:... }, containing the program's
stdout, stderr, and its exit code. Otherwise returns the child process object,
and the callback gets the arguments (code, stdout, stderr).
Note: For long-lived processes, it's best to run exec() asynchronously as
the current synchronous implementation uses a lot of CPU. This should be getting
fixed soon.
Available options:
-v: output a diagnostic for every file processed-c: like verbose but report only when a change is made-R: change files and directories recursivelyExamples:
chmod(755, '/Users/brandon');
chmod('755', '/Users/brandon'); // same as above
chmod('u+x', '/Users/brandon');
Alters the permissions of a file or directory by either specifying the absolute permissions in octal form or expressing the changes in symbols. This command tries to mimic the POSIX behavior as much as possible. Notable exceptions:
Available options:
-a: Change only the access time-c: Do not create any files-m: Change only the modification time-d DATE: Parse DATE and use it instead of current time-r FILE: Use FILE's times instead of current timeExamples:
touch('source.js');
touch('-c', '/path/to/some/dir/source.js');
touch({ '-r': FILE }, '/path/to/some/dir/source.js');
Update the access and modification times of each FILE to the current time. A FILE argument that does not exist is created empty, unless -c is supplied. This is a partial implementation of touch(1).
Available options:
+/-e: exit upon error (config.fatal)+/-v: verbose: show all commands (config.verbose)Examples:
set('-e'); // exit upon first error
set('+e'); // this undoes a "set('-e')"
Sets global configuration variables
Examples:
var tmp = tempdir(); // "/tmp" for most *nix platforms
Searches and returns string containing a writeable, platform-dependent temporary directory. Follows Python's tempfile algorithm.
Tests if error occurred in the last command. Returns null if no error occurred,
otherwise returns string explaining the error
Example:
var sh = require('shelljs');
var silentState = sh.config.silent; // save old silent state
sh.config.silent = true;
/* ... */
sh.config.silent = silentState; // restore old silent state
Suppresses all command output if true, except for echo() calls.
Default is false.
Example:
require('shelljs/global');
config.fatal = true; // or set('-e');
cp('this_file_does_not_exist', '/dev/null'); // dies here
/* more commands... */
If true the script will die on errors. Default is false. This is
analogous to Bash's set -e
Example:
config.verbose = true; // or set('-v');
cd('dir/');
ls('subdir/');
Will print each command as follows:
cd dir/
ls subdir/
FAQs
Portable Unix shell commands for Node.js
We found that shelljs demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 3 open source maintainers collaborating on the project.
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