Code & computing / QUICK REFERENCE

Bash & Linux essentials

Navigate files, inspect text, handle quoting and control a shell without relying on destructive shortcuts.

40 entries

Know where you are

Current directory: pwd
Prints the working directory. [1]
Detailed directory listing: ls -lah
Includes hidden names and human-readable sizes. [1]
Enter a directory: cd "project files"
Quotes preserve the embedded space. [1]
Parent directory: cd ..
Moves up one directory level. [1]
Home directory: cd
Uses your HOME setting. [1]
Previous directory: cd -
Returns to the previous working directory. [1]
Locate an executable: command -v python3
Shows how this shell resolves the command. [1]
Identify command kind: type cd
Distinguishes aliases, functions and builtins. [1]

First twenty lines: head -n 20 notes.txt
Reads the beginning of a text file. [2]
Last twenty lines: tail -n 20 notes.txt
Reads the end of a text file. [2]
Follow a rotating log: tail -F app.log
GNU behavior retries the filename after rotation. [2]
Count lines: wc -l notes.txt
Counts newline characters. [2]
File metadata: stat notes.txt
Shows size, times and permissions. [2]
Disk space by filesystem: df -h
Reports mounted filesystem usage. [2]
Directory disk usage: du -sh logs
Summarizes allocated space beneath logs. [2]
Create nested directories: mkdir -p "project files/output"
Creates absent parents without deleting contents. [2]

Literal text search: grep -nF -- "error" app.log
Prints matching line numbers without regex interpretation. [3]
Case-insensitive search: grep -ni -- "warning" app.log
Case matching follows the active locale. [3]
Recursive fixed-string search: grep -rnF -- "TODO" src
Searches files beneath src. [3]
Exclude matching lines: grep -v -- "debug" app.log
Prints nonmatching lines. [3]
List matching filenames: grep -rlF -- "TODO" src
Emits matching filenames, not matching text. [3]
Find files by suffix: find . -type f -name '*.py'
Quotes keep the shell from expanding the pattern. [4]
Find directories by name: find . -type d -name node_modules
Lists matching directories without deleting them. [4]
Find recent files: find . -type f -mtime -1
Matches files modified within the previous 24 hours. [4]

Literal string: printf '%s\n' '$HOME'
Single quotes keep the dollar sign literal. [1]
Expand a variable safely: printf '%s\n' "$HOME"
Double quotes preserve the value as one argument. [1]
Set a shell variable: project='my project'
No spaces around the assignment operator. [1]
Export to child processes: export PROJECT_NAME='atlas'
Makes the value available to subsequently launched children. [1]
Capture output: today=$(date +%F)
Captures stdout; trailing newlines are removed. [1]
Pipe output to a command: printf '%s\n' one two | wc -l
Sends stdout through the pipe. [1]
Redirect with overwrite: printf '%s\n' draft > notes.txt
Creates or replaces notes.txt: existing contents are lost. [1]
Append to a file: printf '%s\n' next >> notes.txt
Adds to the end instead of truncating. [1]

Move to line start: Ctrl+a
Default Emacs-style readline binding. [1]
Move to line end: Ctrl+e
Default Emacs-style readline binding. [1]
Search previous commands: Ctrl+r
Review the matched command before executing it. [1]
Cancel foreground command: Ctrl+c
Sends an interrupt; applications may handle it differently. [1]
Suspend foreground job: Ctrl+z
Stops, rather than terminates, a job. [1]
List this shell's jobs: jobs
Does not list every system process. [1]
Resume in foreground: fg
Resumes the current job on your terminal. [1]
Show previous exit status: printf '%s\n' "$?"
Run immediately after the command of interest. [1]

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Updated 2026-10-19Bash 5.x / GNU userland

cheatsheetatlas.com/sheets/bash/ · Updated 2026-10-19 · Bash 5.x / GNU userland