Essential Linux Command Cheat Sheet: Master ls, cd, grep, and More

ls – List Directory Contents

The ls command lists files and directories. Frequently used options are: -a: show hidden files (those starting with a dot). -l: display detailed information such as permissions, size, and timestamps. -F: append a symbol to each entry to indicate its type (e.g., * for executables, / for directories).

cd – Change Directory

Use cd <dir> to move into a directory. Special forms: cd or cd ~: go to the current user’s home directory. cd -: return to the previous directory. cd ..: move up one level.

pwd – Print Working Directory

Displays the absolute path of the current directory.

mkdir / rmdir – Create and Remove Directories

mkdir <dir>

creates a directory; rmdir <dir> removes an empty directory. Both support the -p option to create or remove parent directories recursively.

Examples:

mkdir -p 1/2/3
rmdir -p 1/2/3

cp – Copy Files and Directories

Basic forms: cp 1.txt ../test2: copy a file to another directory. cp 1.txt 2.txt: copy and rename. cp -r a b: copy directory a recursively to b.

mv – Move or Rename Files

Examples: mv 1.txt ../test1: move a file. mv 1.txt 2.txt: rename a file. mv 1.txt ../test1/2.txt: move and rename simultaneously.

rm – Remove Files and Directories

Common options: -i: prompt before each deletion. -r: remove directories recursively. -f: force deletion without prompts.

du / df – Disk Usage

du

shows the space used by files or directories; df reports free space on mounted filesystems.

Examples: du -hs ./*: human‑readable size of each item in the current directory.

cat – Concatenate and Display Files

Displays file contents or concatenates multiple files. Redirection operators can be used, e.g., cat file1 file2 > file3 to combine files.

echo – Print Text

Outputs strings to standard output. Syntax: echo [-ne] [string]. Options: -n: omit trailing newline. -e: enable backslash‑escaped characters (e.g., \n for newline).

Examples:

echo "123" "456"   # prints: 123 456
echo -e "123
456" # prints on two lines

more / less – Paginated Viewing

Both allow scrolling through long files. more pauses at each screenful; less supports forward and backward navigation with keys such as Space, b, g, G, and search with /pattern.

head / tail – Show File Beginnings or Ends

head -n 10 file

shows the first 10 lines; tail -n 10 file shows the last 10 lines. tail -f file follows a file in real time.

wc – Word Count

Counts lines, words, and bytes. Options: -l: lines -w: words -c: bytes

grep – Search Text with Patterns

Searches for lines matching a regular expression. Returns 0 on success, 1 on no match, 2 if a file is missing, making it useful in scripts.

Examples:

ls -l | grep '^a'          # lines starting with 'a'
grep 'test' d*           # lines containing 'test' in files starting with 'd'
grep -E 'w(es)t.*/1' aa   # using extended regex

man – Manual Pages

Displays detailed documentation for commands, e.g., man ls. Most commands also support --help.

logout – End Session

Logs out of the current shell, the counterpart of login.

Pipes and xargs – Combining Commands

The pipe symbol | feeds the output of one command as input to the next. xargs builds command lines from standard input, useful when a command expects arguments rather than piped data.

Examples:

find / -name "core" -print | xargs echo "" > /tmp/core.log
ls | xargs rm

basename / dirname – Path Manipulation

basename /path/file.txt

returns file.txt; dirname /path/file.txt returns /path.

set – Show Shell Variables

Running set without arguments lists all shell variables and functions.