Essential Linux Shell Commands Every Developer Should Know

This article compiles a handy reference of frequently used Linux shell commands, organized as concise one‑liners that can be copied and executed directly in a terminal. It covers a wide range of tasks such as network checks, process control, file manipulation, Git workflow, system monitoring, and more.

Network and Port Checks

echo >/dev/tcp/8.8.8.8/53 && echo "open"

– Test if a remote TCP port is reachable. ssh -vvv user@ip_address – Enable verbose SSH debugging. ssh user@ip_address -i key.pem – Connect using a PEM key. nmap -p 8081 172.20.0.0/16 – Scan a subnet for open ports. curl -I http://www.example.com – Retrieve HTTP headers. curl -sL -w "%{http_code}\n" www.example.com -o /dev/null – Get only the HTTP status code.

echo "hosts.sampleHost 10 `date +%s`" | nc 192.168.200.2 3000

– Send data to a Graphite server via netcat.

Process Management

Ctrl+z

– Suspend a running process and move it to the background. fg – Bring the most recent background job to the foreground. ps axwef – Display a detailed process tree. watch ps -ef – Repeatedly run ps -ef to monitor processes. kill -l – List all signal names. kill -9 $$ – Terminate the current shell (useful to skip history entry).

File and Text Operations

openssl rand -hex n

– Generate a random hexadecimal string of length n. source /home/user/file.name – Execute commands from a file in the current shell. ${variable:0:5} – Extract the first five characters of a variable.

dd if=/dev/zero of=/tmp/output.img bs=8k count=256k; rm -rf /tmp/output.img

– Benchmark disk write speed. hdparm -Tt /dev/sda – Benchmark disk read speed. echo -n "text" | md5sum – Compute the MD5 hash of a string. xmllint --noout file.xml – Validate XML syntax. tar zxvf package.tar.gz -C new_dir – Extract a tar.gz archive into a new directory. unzip package_name.zip -d dir_name – Unzip a file to a specific folder. mkdir -p /home/user/{test,test1,test2} – Create multiple directories in one command. find /home/user -maxdepth 1 -type d -empty – List empty sub‑directories. find -iname "*txt*" -exec mv -v {} /home/user \; – Move all files containing "txt" in their name. paste test.txt test1.txt – Display two files side‑by‑side. expand test.txt > test1.txt – Convert tabs to spaces. printf '%100s\n' | tr ' ' = – Print a line of 100 equal signs.

Git Workflow

git clone [email protected]:name/app.git -b master

– Clone a specific branch. git checkout develop – Switch to another branch. git branch -d myfeature – Delete a local branch. git push origin :branchName – Delete a remote branch. git push -u origin mynewfeature – Push a new branch and set upstream. git config --global user.email "[email protected]" – Set global Git email. git pull --rebase origin master – Rebase local commits onto the latest master.

System Utilities

mount -o remount,rw /

– Remount root filesystem as read/write. mount --bind /source /destination – Bind‑mount a directory. mount -t tmpfs tmpfs /tmpram -o size=512m – Create a RAM‑disk.

nsupdate <<EOF
update add $HOST 86400 A $IP
send
EOF

– Dynamically update DNS records. pv data.log – Show a progress bar while copying data. stat -c %U file.txt – Get the owner of a file. lsblk -f – List block devices with filesystem info. find . -type f -exec egrep -l " +$" {} \; – Find files whose names end with spaces. find . -type f -exec egrep -l $'\t' {} \; – Find files containing tab characters.

split –b 100m /path/to/large/archive /path/to/output/files
cat files* > archive

– Split and re‑assemble a large tar.gz.

History and Convenience

!100

– Execute command number 100 from history. !cat:p – Print the most recent cat command. !cat – Re‑run the last cat command. sudo !! – Re‑run the previous command with sudo. cd - – Return to the previous working directory. vim + some_file_name – Open Vim and jump to the end of a file.

Miscellaneous

cat > test.txt

– Enter multi‑line input (terminate with Ctrl+D). > test.txt – Truncate or create an empty file. echo "some text" | sudo tee -a /path/file – Append text to a file with elevated privileges. grep -r "some_text" /path/to/dir – Recursively search for a string. grep -w "name" test.txt – Search for whole‑word matches.

lsof / | awk '{ if($7 > 1048576) print $7/1048576 "MB " $9 }' | sort -n -u | tail

– List the ten largest open files. find . -type f -exec egrep -l " +$" {} \; – Find files with trailing spaces in their names.

This cheat‑sheet serves as a quick‑lookup guide for developers, system administrators, and anyone working with Bash on Linux, enabling them to perform common tasks efficiently without having to search for individual command syntax.