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head Command Cheat Sheet

head prints the first part (default 10 lines) of each given file. It is the counterpart to tail.

Synopsis

head [OPTION]... [FILE]...

Basic Usage

Show First 10 Lines

head filename.txt

Show First N Lines (-n)

head -n 20 filename.txt
Or simply: 
head -20 filename.txt

Advanced Options

Show First N Bytes (-c)

Useful for binary files or specific data extraction.

head -c 100 image.png
(Displays first 100 bytes).

Suffixes allowed: - b: 512 - kB: 1000 - K: 1024 - MB: 10001000 - M: 10241024

head -c 1M large.iso > header.img

Show All EXCEPT Last N Lines

Negative numbers with -n print everything except the last N lines.

head -n -5 filename.txt
(Prints the whole file, stopping 5 lines before the end).

Multiple Files

When multiple files are provided, head prints a header ==> filename <== before each one.

head file1.txt file2.txt
Output: 
==> file1.txt <==
Line 1...
Line 2...

==> file2.txt <==
Line 1...

Suppress Headers (-q): Quiet mode. Never print headers.

head -q file1.txt file2.txt

Always Print Headers (-v): Verbose mode. Print headers even for a single file.

head -v file1.txt

Pipeline Examples

View Top Processes

Combine with ps and sort.

ps aux --sort=-%mem | head -n 6
(Shows header + top 5 memory consuming processes).

Verify Archive Integrity

Check the first few bytes of a file to verify its type signature.

head -c 4 file.pdf
# Output: %PDF

Random Password Generation

Limit the output of /dev/urandom.

tr -dc 'A-Za-z0-9' < /dev/urandom | head -c 16; echo

Exit Status

Code Meaning
0 Success
1 Error reading file

Notes

  • head reads from Standard Input if no file is specified.
  • It stops reading as soon as the limit is reached, making it efficient for large files (unlike cat).