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Bash Scripting Cheat Sheet: Commands You Use Daily (2026)

April 16, 2026 5 min read

Bash scripting is more than just a way to automate tasks; it’s a powerful tool for manipulating data and controlling your system’s behavior.

Let’s see some common commands in action. Imagine you have a log file, app.log, and you want to find all lines containing "ERROR" that occurred in the last hour.

# Get the current hour in HH format
current_hour=$(date +"%H")

# Filter the log file for lines containing "ERROR" and the current hour
grep "ERROR" app.log | awk -v hour="$current_hour" '$0 ~ hour'

This snippet demonstrates how grep and awk can be chained together to perform sophisticated filtering. grep finds lines matching a pattern, and awk processes those lines further, in this case, by checking if the line contains the current hour.

Here’s a breakdown of commands you’ll likely encounter and use daily:

File and Directory Operations:

  • ls: List directory contents.
    • ls -l: Long listing format, showing permissions, owner, size, and modification date.
    • ls -a: Show all files, including hidden ones (starting with .).
  • cd: Change directory.
    • cd ..: Move up one directory.
    • cd ~: Go to your home directory.
    • cd -: Go to the previous directory you were in.
  • pwd: Print working directory. Shows your current location in the filesystem.
  • mkdir: Make directories.
    • mkdir -p projects/web/frontend: Creates nested directories if they don’t exist.
  • rm: Remove files or directories.
    • rm myfile.txt: Removes myfile.txt.
    • rm -r mydir: Removes mydir and its contents recursively. Use with extreme caution!
    • rm -f important.config: Force removal without prompting. Use with extreme caution!
  • cp: Copy files and directories.
    • cp source.txt destination.txt: Copies source.txt to destination.txt.
    • cp -r sourcedir destdir: Copies sourcedir and its contents to destdir.
  • mv: Move or rename files and directories.
    • mv oldname.txt newname.txt: Renames oldname.txt to newname.txt.
    • mv file.txt /path/to/new/location/: Moves file.txt to a different directory.
  • touch: Create empty files or update timestamps.
    • touch newfile.log: Creates newfile.log if it doesn’t exist.

Text Processing and Searching:

  • cat: Concatenate and display file content.
    • cat file1.txt file2.txt: Displays content of both files.
    • cat file.txt: Displays content of file.txt.
  • grep: Search for patterns in text.
    • grep "pattern" filename: Finds lines containing "pattern" in filename.
    • grep -i "error" logfile.txt: Case-insensitive search for "error".
    • grep -v "debug" logfile.txt: Invert match, showing lines without "debug".
    • grep -r "config" /etc/: Recursively search for "config" in /etc/.
  • sed: Stream editor for filtering and transforming text.
    • sed 's/old/new/g' filename: Replaces all occurrences of "old" with "new" in filename.
    • sed -i 's/localhost/192.168.1.100/g' myconfig.conf: Edits myconfig.conf in-place, replacing "localhost" with "192.168.1.100".
  • awk: Pattern scanning and processing language. Powerful for structured text.
    • awk '{print $1, $3}' data.txt: Prints the first and third fields of each line in data.txt.
    • awk -F',' '$2 > 10 {print $1}' csvdata.csv: If the second field (comma-separated) is greater than 10, print the first field.
  • sort: Sort lines of text files.
    • sort names.txt: Sorts names.txt alphabetically.
    • sort -n numbers.txt: Sorts numbers.txt numerically.
    • sort -r data.txt: Sorts data.txt in reverse order.
  • uniq: Report or omit repeated lines. Often used after sort.
    • sort data.txt | uniq: Shows unique lines from data.txt.
    • sort data.txt | uniq -c: Counts occurrences of each unique line.

Process Management:

  • ps: Report a snapshot of the current processes.
    • ps aux: Shows all processes for all users in BSD format.
    • ps -ef: Shows all processes in System V format.
  • top: Display dynamic real-time view of running processes.
  • kill: Send a signal to a process (default is TERM, to terminate).
    • kill 1234: Sends SIGTERM to process ID 1234.
    • kill -9 1234: Sends SIGKILL to process ID 1234 (force kill).
  • nohup: Run a command immune to hangups, with output to a nohup.out file.
    • nohup ./my_long_script.sh &: Runs the script in the background, immune to terminal closure.

System Information and Networking:

  • df: Report file system disk space usage.
    • df -h: Human-readable output (e.g., KB, MB, GB).
  • du: Estimate file space usage.
    • du -sh /var/log: Summarizes disk usage for /var/log in human-readable format.
  • ping: Send ICMP ECHO_REQUEST to network hosts.
    • ping google.com: Checks network connectivity to google.com.
  • ssh: OpenSSH remote login client.
    • ssh user@remote_host: Connects to remote_host as user.
  • scp: Secure copy (remote file copy program).
    • scp localfile.txt user@remote_host:/remote/path/: Copies localfile.txt to the remote server.
  • curl: Transfer data from or to a server.
    • curl -O https://example.com/data.zip: Downloads data.zip from the URL.

Permissions and Ownership:

  • chmod: Change file mode bits (permissions).
    • chmod +x script.sh: Adds execute permission to script.sh.
    • chmod 755 script.sh: Sets permissions to rwxr-xr-x.
  • chown: Change file owner and group.
    • chown user:group filename: Changes owner to user and group to group for filename.

The power of these commands often lies in their ability to be combined. For instance, you can create a script to automatically back up your web server’s configuration files:

#!/bin/bash

BACKUP_DIR="/opt/backups/configs/$(date +%Y%m%d_%H%M%S)"
mkdir -p "$BACKUP_DIR"
cp -r /etc/nginx "$BACKUP_DIR"
cp -r /etc/apache2 "$BACKUP_DIR"
tar -czvf "$BACKUP_DIR.tar.gz" "$BACKUP_DIR"
rm -rf "$BACKUP_DIR"
echo "Backup created at $BACKUP_DIR.tar.gz"

This script creates a timestamped directory, copies configuration directories, compresses them into a tarball, and then cleans up the intermediate directory.

One subtle but incredibly useful aspect of shell scripting is understanding shell expansion, particularly brace expansion. While it might seem like a minor feature, it can drastically simplify repetitive tasks. For example, echo file_{a,b,c}.txt expands to file_a.txt file_b.txt file_c.txt without you having to type each one. This applies to ranges too: seq 1..5 generates numbers from 1 to 5. This capability extends to creating multiple directories or files with slightly varied names, saving significant typing.

As you become more comfortable, you’ll explore more advanced features like shell variables, conditional statements (if, else), loops (for, while), and functions. Understanding how to pipe output from one command to another is fundamental to efficient shell usage.

Next, you’ll likely want to learn about managing background processes and job control.

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