Viewing Text Files

Linux provides several commands to read or preview the contents of text files directly from the terminal.

cat – Concatenate and Display File

Displays the entire contents of a file.

Syntax

cat filename

Usage

cat /etc/passwd

Flags

• -n: Number all output lines
• -b: Number non-blank lines

Notes

• Not ideal for large files (scrolls entire content rapidly).

head – View Beginning of File

Shows the first 10 lines by default.

Syntax

head filename

Usage

head -n 15 error.log  # First 15 lines

Flags

• -n <number>: Number of lines to display

tail – View End of File

Shows the last 10 lines by default.

Syntax

tail filename

Usage

tail -n 20 access.log  # Last 20 lines

Flags

• -n <number>: Number of lines
• -f: Follow the file (live update as new lines are added, useful for logs)

Example

tail -f /var/log/syslog

less – Scrollable Viewer

Allows scrolling through a file page by page and line by line.

Syntax

less filename

Usage

less /var/log/dmesg

Navigation inside less

• SPACE: Next page
• b: Back one page
• q: Quit
• /pattern: Search
• n: Next search result

Summary Table