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Eric Hu

Essential Linux Commands

Linux is the operating system behind most web servers, containers, and cloud infrastructure.

Knowing the related command line tools is essential for deploying and debugging web applications.

This cheatsheet provides a quick reference to the Linux commands web developers use most.

Command	Description
`pwd`	Print the current working directory.
`ls`	List files and directories.
`cd`	Change directory.
`mkdir`	Create a directory.
`touch`	Create an empty file or update its timestamp.
`cp`	Copy files and directories.
`mv`	Move or rename files and directories.
`rm`	Delete files and directories.
`cat`	Print the contents of a file.
`less`	View a file page by page.
`head`	Show the first lines of a file.
`tail`	Show the last lines of a file, or follow it live.

Command	Description
`grep`	Search for text patterns in files.
`find`	Find files and directories by name or attributes.
`chmod`	Change file permissions.
`chown`	Change file ownership.
`ps`	List running processes.
`kill`	Stop a process by ID.
`top`	Monitor processes and resource usage live.
`df`	Show disk space usage.
`du`	Show the size of files and directories.
`curl`	Make HTTP requests from the terminal.
`ssh`	Connect to a remote server.
`scp`	Copy files between machines over SSH.

Navigating the file system

Print the current directory.

bash

pwd

List files and directories.

bash

ls

List files and directories, including hidden files and details.

bash

ls -la

Change directory.

bash

cd /var/www
cd ..        # up one level
cd ~         # home directory
cd -         # previous directory

Working with files and directories

Create directories.

bash

mkdir projects

Create nested directories.

bash

mkdir -p projects/app/src

Create an empty file.

bash

touch index.html

Copy files and directories.

bash

cp file.txt backup.txt
cp -r src/ dist/

Move or rename files.

bash

mv old-name.txt new-name.txt
mv file.txt /var/www/

Delete files and directories.

bash

rm file.txt
rm -r node_modules/

Viewing files

Print an entire file.

bash

cat config.json

View a file page by page. Press q to quit.

bash

less /var/log/syslog

Show the first or last lines of a file.

bash

head -n 20 app.log
tail -n 20 app.log

Follow a log file live.

bash

tail -f /var/log/nginx/access.log

Searching and finding

Search for text inside files.

bash

grep "TODO" app.js

Recusively search for text in a directory.

bash

grep -r "apiKey" src/

Search with case-insensitive matching.

bash

grep -i "error" server.log

Find files by name or type.

bash

find . -name "*.test.js"
find /var/www -type d -name "uploads"

Permissions

Change file ownership.

bash

sudo chown www-data:www-data /var/www/html

Recursively change ownership of a directory.

bash

sudo chown -R $USER:$USER projects/

Change file permissions.

bash

chmod 644 index.html

Each digit represents permissions for Owner, Group, and Others (in that order).

Code	Binary	Symbolic	Permissions
0	000	`---`	No permissions
1	001	`--x`	Execute only
2	010	`-w-`	Write only
3	011	`-wx`	Write + Execute
4	100	`r--`	Read only
5	101	`r-x`	Read + Execute
6	110	`rw-`	Read + Write
7	111	`rwx`	Read + Write + Execute

Examples:

Value	Meaning
`644`	Owner reads/writes, others read.
`755`	Owner does everything, others read and execute.
`600`	Owner reads/writes only.

You can use symbolic mode to add or remove permissions:

bash

chmod +x deploy.sh

Symbol	Meaning
u	User/Owner
g	Group
o	Others
a	All (u+g+o)
+	Add permission
-	Remove permission
=	Set exact permission

Examples:

Command	Effect
`chmod u+x file`	Add execute to owner
`chmod go-w file`	Remove write from group & others
`chmod a=r file`	Set read-only for all
`chmod u=rwx,go=rx file`	Set `755` permissions
`chmod +x file`	Add execute to all users
`chmod -x file`	Remove execute from all users

Processes

List running processes.

bash

ps aux

List processes and filter by name.

bash

ps aux | grep node

Monitor processes live. Press q to quit.

bash

top

Stop a process.

bash

kill 1234

Stop a process forcefully.

bash

kill -9 1234

Disk usage

Show disk space on all file systems.

bash

df -h

Show the size of directories.

bash

du -sh node_modules/
du -sh */

Networking

Make an HTTP request.

bash

curl https://api.example.com/users
curl -X POST -H "Content-Type: application/json" -d '{"name":"Ada"}' https://api.example.com/users

Check if a host is reachable.

bash

ping example.com

Show open ports and connections.

bash

ss -tuln

Package management

Install and update packages on Debian/Ubuntu.

bash

sudo apt update
sudo apt install nginx
sudo apt upgrade

Install packages on Fedora/RHEL.

bash

sudo dnf install nginx

SSH and remote access

Connect to a remote server.

bash

ssh user@server.com
ssh -i ~/.ssh/key.pem user@server.com

Copy files to and from a remote server.

bash

scp file.txt user@server.com:/var/www/
scp user@server.com:/var/log/app.log ./

Environment variables

Print an environment variable.

bash

echo $PATH

Set a variable for the current session.

bash

export NODE_ENV=production

Run a command with a variable set.

bash

NODE_ENV=production node server.js

Shortcuts and tips

Chain commands.

bash

mkdir app && cd app
npm run build || echo "Build failed"

Rerun the last command, or rerun it with sudo.

bash

!!
sudo !!

Search your command history.

bash

history | grep ssh

Press Ctrl + R to search history interactively, and Tab to autocomplete paths and commands.

❤ Like

🔖 Save

🔗 Share

Eric Hu

Essential Linux Commands

Linux is the operating system behind most web servers, containers, and cloud infrastructure.

Knowing the related command line tools is essential for deploying and debugging web applications.

This cheatsheet provides a quick reference to the Linux commands web developers use most.

Command	Description
`pwd`	Print the current working directory.
`ls`	List files and directories.
`cd`	Change directory.
`mkdir`	Create a directory.
`touch`	Create an empty file or update its timestamp.
`cp`	Copy files and directories.
`mv`	Move or rename files and directories.
`rm`	Delete files and directories.
`cat`	Print the contents of a file.
`less`	View a file page by page.
`head`	Show the first lines of a file.
`tail`	Show the last lines of a file, or follow it live.

Command	Description
`grep`	Search for text patterns in files.
`find`	Find files and directories by name or attributes.
`chmod`	Change file permissions.
`chown`	Change file ownership.
`ps`	List running processes.
`kill`	Stop a process by ID.
`top`	Monitor processes and resource usage live.
`df`	Show disk space usage.
`du`	Show the size of files and directories.
`curl`	Make HTTP requests from the terminal.
`ssh`	Connect to a remote server.
`scp`	Copy files between machines over SSH.

Navigating the file system

Print the current directory.

bash

pwd

List files and directories.

bash

ls

List files and directories, including hidden files and details.

bash

ls -la

Change directory.

bash

cd /var/www
cd ..        # up one level
cd ~         # home directory
cd -         # previous directory

Working with files and directories

Create directories.

bash

mkdir projects

Create nested directories.

bash

mkdir -p projects/app/src

Create an empty file.

bash

touch index.html

Copy files and directories.

bash

cp file.txt backup.txt
cp -r src/ dist/

Move or rename files.

bash

mv old-name.txt new-name.txt
mv file.txt /var/www/

Delete files and directories.

bash

rm file.txt
rm -r node_modules/

Viewing files

Print an entire file.

bash

cat config.json

View a file page by page. Press q to quit.

bash

less /var/log/syslog

Show the first or last lines of a file.

bash

head -n 20 app.log
tail -n 20 app.log

Follow a log file live.

bash

tail -f /var/log/nginx/access.log

Searching and finding

Search for text inside files.

bash

grep "TODO" app.js

Recusively search for text in a directory.

bash

grep -r "apiKey" src/

Search with case-insensitive matching.

bash

grep -i "error" server.log

Find files by name or type.

bash

find . -name "*.test.js"
find /var/www -type d -name "uploads"

Permissions

Change file ownership.

bash

sudo chown www-data:www-data /var/www/html

Recursively change ownership of a directory.

bash

sudo chown -R $USER:$USER projects/

Change file permissions.

bash

chmod 644 index.html

Each digit represents permissions for Owner, Group, and Others (in that order).

Code	Binary	Symbolic	Permissions
0	000	`---`	No permissions
1	001	`--x`	Execute only
2	010	`-w-`	Write only
3	011	`-wx`	Write + Execute
4	100	`r--`	Read only
5	101	`r-x`	Read + Execute
6	110	`rw-`	Read + Write
7	111	`rwx`	Read + Write + Execute

Examples:

Value	Meaning
`644`	Owner reads/writes, others read.
`755`	Owner does everything, others read and execute.
`600`	Owner reads/writes only.

You can use symbolic mode to add or remove permissions:

bash

chmod +x deploy.sh

Symbol	Meaning
u	User/Owner
g	Group
o	Others
a	All (u+g+o)
+	Add permission
-	Remove permission
=	Set exact permission

Examples:

Command	Effect
`chmod u+x file`	Add execute to owner
`chmod go-w file`	Remove write from group & others
`chmod a=r file`	Set read-only for all
`chmod u=rwx,go=rx file`	Set `755` permissions
`chmod +x file`	Add execute to all users
`chmod -x file`	Remove execute from all users

Processes

List running processes.

bash

ps aux

List processes and filter by name.

bash

ps aux | grep node

Monitor processes live. Press q to quit.

bash

top

Stop a process.

bash

kill 1234

Stop a process forcefully.

bash

kill -9 1234

Disk usage

Show disk space on all file systems.

bash

df -h

Show the size of directories.

bash

du -sh node_modules/
du -sh */

Networking

Make an HTTP request.

bash

curl https://api.example.com/users
curl -X POST -H "Content-Type: application/json" -d '{"name":"Ada"}' https://api.example.com/users

Check if a host is reachable.

bash

ping example.com

Show open ports and connections.

bash

ss -tuln

Package management

Install and update packages on Debian/Ubuntu.

bash

sudo apt update
sudo apt install nginx
sudo apt upgrade

Install packages on Fedora/RHEL.

bash

sudo dnf install nginx

SSH and remote access

Connect to a remote server.

bash

ssh user@server.com
ssh -i ~/.ssh/key.pem user@server.com

Copy files to and from a remote server.

bash

scp file.txt user@server.com:/var/www/
scp user@server.com:/var/log/app.log ./

Environment variables

Print an environment variable.

bash

echo $PATH

Set a variable for the current session.

bash

export NODE_ENV=production

Run a command with a variable set.

bash

NODE_ENV=production node server.js

Shortcuts and tips

Chain commands.

bash

mkdir app && cd app
npm run build || echo "Build failed"

Rerun the last command, or rerun it with sudo.

bash

!!
sudo !!

Search your command history.

bash

history | grep ssh

Press Ctrl + R to search history interactively, and Tab to autocomplete paths and commands.

Essential Linux Commands

Navigating the file system

Working with files and directories

Viewing files

Searching and finding

Permissions

Processes

Disk usage

Networking

Package management

SSH and remote access

Environment variables

Shortcuts and tips

Full-Stack AI Developer Roadmap

Essential Linux Commands

Navigating the file system

Working with files and directories

Viewing files

Searching and finding

Permissions

Processes

Disk usage

Networking

Package management

SSH and remote access

Environment variables

Shortcuts and tips

Full-Stack AI Developer Roadmap