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JSH
Core Commands

Core Commands

JSH includes a small set of built-in shell-style commands for navigating directories, reading files, printing text, creating and removing paths, and waiting for a period of time.

Overview

Most commands are implemented as JavaScript files under /sbin and are resolved through the JSH command path. The cd command is different: it is an internal shell command because it must change the current shell working directory.

Notes

  • These commands operate inside the JSH virtual filesystem, not directly on the host OS filesystem.
  • Relative paths are resolved from the current JSH working directory.
  • cd affects the active shell session, while commands such as pwd, ls, and rm run as normal commands.
  • Some commands intentionally provide a smaller feature set than their Unix counterparts.

cat

Concatenates files to standard output. It also supports line formatting options and optional syntax highlighting for selected file types.

Syntax
cat [OPTION]... [FILE]...
Options
  • -n, --number number all output lines
  • -E, --showEnds display $ at the end of each line
  • -T, --showTabs display tab characters as ^I
  • -s, --squeeze suppress repeated empty lines
  • -c, --color enable syntax highlighting
  • -h, --help show help

With -c, syntax highlighting is supported for these extensions:

  • .js
  • .json
  • .ndjson
  • .sql
  • .csv
  • .yaml
  • .yml
  • .toml
Usage example
/work > cat -n notes.txt
/work > cat -c script.js
/work > cat -sE log.txt

cd

Changes the current working directory of the active JSH shell session. Unlike most other commands, cd is an internal command and is not implemented as a separate /sbin/*.js file.

Syntax
cd <directory>

If the target directory does not exist, cd prints an error and returns a non-zero status.

Usage example
/work > cd subdir
/work/subdir >

echo

Prints its arguments separated by spaces and terminates with a newline.

Syntax
echo [ARG]...

echo does not currently implement shell-style flags such as -n or escape interpretation. It simply prints the arguments exactly as they are passed.

Usage example
/work > echo hello world
hello world

ls

Lists directory contents. By default it prints entries in columns with colorized names.

Syntax
ls [OPTION]... [PATH]...
Options
  • -l, --long use a detailed listing view
  • -a, --all include hidden entries
  • -t, --time sort by modification time, newest first
  • -R, --recursive list subdirectories recursively

If no path is given, ls uses the current working directory. It also accepts simple wildcard patterns such as * and ? in path arguments.

Usage example
/work > ls
/work > ls -la
/work > ls -t /lib
/work > ls -R src
/work > ls *.js

mkdir

Creates one or more directories.

Syntax
mkdir [OPTION]... DIRECTORY...
Options
  • -p, --parents create parent directories as needed
  • -v, --verbose print a message for each created directory
  • -h, --help show help

Without -p, creating an existing directory reports an error. With -p, existing directories are accepted.

Usage example
/work > mkdir data
/work > mkdir -p logs/app/2026
/work > mkdir -pv build/output

pwd

Prints the current working directory.

Syntax
pwd
Usage example
/work > pwd
/work

rm

Removes files or directories.

Syntax
rm [OPTION]... FILE...
Options
  • -r, -R, --recursive remove directories and their contents recursively
  • -d, --dir, --directory remove empty directories
  • -f, --force ignore nonexistent paths and suppress missing operand errors
  • -v, --verbose print a message for each removed path
  • -h, --help show help

Important behavior:

  • Removing a directory without -r or -d reports Is a directory
  • -d only removes empty directories
  • -R is treated the same as -r
  • --directory is treated the same as --dir
Usage example
/work > rm old.txt
/work > rm -rf cache
/work > rm -d empty-dir
/work > rm -fv temp.txt missing.txt

sleep

Waits for the specified number of seconds before returning.

Syntax
sleep [options] <sec>
Options
  • -h, --help show help

The value is interpreted as seconds.

Usage example
/work > sleep 5
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