Command Reference

Nash includes 28 built-in commands that provide essential Unix/Linux command-line functionality entirely within the sandbox. Unlike traditional shells that invoke system binaries, Nash commands operate exclusively through the Virtual Filesystem (VFS) API—no system processes are ever spawned.

All Nash commands are built-in and sandboxed. They never invoke system binaries or access the host filesystem directly (except through explicit --bind mounts).

File Operations

cat, cp, mv, rm, touch, file, stat

Directory Operations

ls, cd, pwd, mkdir, tree, find

Text Processing

grep, sed, cut, sort, uniq, wc, head, tail

Data Processing

jq - JSON query and manipulation

Environment

env, export, unset

Utilities

echo, clear, help, history, which, test, true, false

File Operations

Commands for reading, writing, and manipulating files.

cat

Concatenate and print files

cp

Copy files and directories

mv

Move or rename files

rm

Remove files and directories

touch

Create empty files or update timestamps

file

Determine file type from magic bytes

stat

Display file status and metadata

Directory Operations

Commands for navigating and managing directories.

ls

List directory contents

cd

Change current directory

pwd

Print working directory path

mkdir

Create directories

tree

Display directory tree structure

find

Search for files in directory hierarchy

Text Processing

Commands for filtering, transforming, and analyzing text.

grep

Search for patterns in text

sed

Stream editor for text transformation

cut

Extract fields from lines

sort

Sort lines of text

uniq

Filter duplicate lines

wc

Count lines, words, and bytes

head

Output first part of files

tail

Output last part of files

Data Processing

jq

JSON processor — Query and transform JSON data with .key, keys, values, length, type, and .[] operators

Environment

Commands for managing environment variables.

env

Display all environment variables

export

Set environment variables

unset

Remove environment variables

Utilities

General-purpose utility commands.

echo

Print text to stdout

clear

Clear the terminal screen

help

Display command reference

history

Show command history

which

Locate command in Nash builtins

test / [

Evaluate conditional expressions

true

Return success (exit code 0)

false

Return failure (exit code 1)

Complete Command Reference

Full Command Table with Descriptions and Flags

Command	Description	Key Flags
`cat`	Print files or pass-through stdin	None
`cd`	Change directory	Special: `cd -` (previous), `cd` (home)
`clear`	Clear terminal screen	None
`cp`	Copy files	None
`cut`	Cut fields from lines	`-d` delimiter, `-f` fields, `-c` characters
`echo`	Print text	`-n` no newline, `-e` escape sequences
`env`	List environment variables	None
`export`	Set environment variable	Format: `KEY=VALUE`
`false`	Exit with code 1	None
`file`	Detect file type	Uses magic bytes + extension heuristic
`find`	Search for files	`-name` glob, `-type` f\|d, `-maxdepth` N
`grep`	Filter lines by pattern	`-v` invert, `-i` ignore case, `-n` line numbers
`head`	First N lines	`-n N` number of lines
`help`	Full command reference	None
`history`	Show command history	Optional: `history N` to limit
`jq`	Process JSON	`.key`, `keys`, `values`, `length`, `type`, `.[]`
`ls`	List directory	`-l` long format, `-a` show hidden
`mkdir`	Create directory	`-p` create parents
`mv`	Move or rename files	None
`pwd`	Print working directory	None
`rm`	Remove files/directories	`-r` recursive, `-f` force (combine as `-rf`)
`sed`	Stream editor	`s/old/new/[g]`, `Nd` delete line N, `d` delete all
`sort`	Sort lines	`-r` reverse, `-u` unique
`stat`	File status	Shows size, type, path
`tail`	Last N lines	`-n N` number of lines
`test` / `[`	Evaluate expressions	`-f` file, `-d` dir, `-e` exists, `-z` empty, `-n` not empty, `=` equals, `-eq` numeric equal
`touch`	Create empty file	None
`tree`	Directory tree view	`-L N` max depth, `-a` show hidden
`true`	Exit with code 0	None
`uniq`	Filter adjacent duplicates	`-c` count, `-d` duplicates only, `-u` unique only
`unset`	Unset environment variable	None
`wc`	Count lines/words/bytes	`-l` lines, `-w` words, `-c` bytes
`which`	Check if command is builtin	None

Differences from Standard Unix Commands

Nash commands are compatible subsets of their Unix counterparts. They implement the most commonly used flags and behaviors, but not every advanced feature.

Key Compatibility Notes

Regular Expressions

Nash’s grep and sed use substring matching, not full regex. Complex patterns like ^start.*end$ or \d+ are not supported.

Glob Patterns

find -name supports minimal glob: * (any chars) and ? (single char). Character classes like [0-9] are not supported.

JSON Processing

jq supports basic operations (.key, keys, values, length, type, .[]) but not advanced queries, filters, or transformations like select(), map(), or recursive descent.

Permissions

ls -l shows fixed permissions. Nash VFS doesn’t implement full Unix permission modes or ownership.

Exit Codes

Commands follow Unix conventions: 0 for success, 1 for errors, 2 for usage errors. Use $? to check exit status.

Command Examples

File Processing Pipeline

# Find all .txt files, search for pattern, count matches
find /home/user -name "*.txt" | while read f; do grep -i "error" "$f"; done | wc -l

Directory Tree Analysis

# Show directory tree with 2 levels, including hidden files
tree -L 2 -a /home/user

JSON Data Extraction

# Extract all keys from JSON file
cat data.json | jq keys

# Get specific field
cat config.json | jq .database.host

Text Transformation

# Sort unique lines from multiple files
cat *.log | sort -u > combined.log

# Replace text in stream
cat input.txt | sed 's/old/new/g' > output.txt

Conditional Execution

# Check if file exists before processing
test -f config.json && echo "Config found" || echo "Missing config"

# Using bracket syntax
[ -d /var/log ] && cd /var/log

Next Steps

View Individual Commands

Detailed documentation for each command

Shell Syntax

Learn about pipes, redirects, and operators

Scripting Guide

Write Nash shell scripts

VFS Overview

Understand the Virtual Filesystem

Overview

File Operations

Directory Operations

Text Processing

Data Processing

Environment & Shell

Utilities

​Quick Navigation

File Operations

Directory Operations

Text Processing

Data Processing

Environment

Utilities

​File Operations

cat

cp

mv

rm

touch

file

stat

​Directory Operations

ls

cd

pwd

mkdir

tree

find

​Text Processing

grep

sed

cut

sort

uniq

wc

head

tail

​Data Processing

jq

​Environment

env

export

unset

​Utilities

echo

clear

help

history

which

test / [

true

false

​Complete Command Reference

​Differences from Standard Unix Commands

​Key Compatibility Notes

​Command Examples

​File Processing Pipeline

​Directory Tree Analysis

​JSON Data Extraction

​Text Transformation

​Conditional Execution

​Next Steps

View Individual Commands

Shell Syntax

Scripting Guide

VFS Overview

Build docs developers (and LLMs) love

Quick Navigation

File Operations

Directory Operations

Text Processing

Data Processing

Environment

Utilities

Complete Command Reference

Differences from Standard Unix Commands

Key Compatibility Notes

Command Examples

File Processing Pipeline

Directory Tree Analysis

JSON Data Extraction

Text Transformation

Conditional Execution

Next Steps