Master Linux File Viewing: head, tail, more, less, and cat Explained

1. head command

The head command displays the first ten lines of a file by default. Syntax: head [options] [file(s)]. Example to show the first ten lines of /etc/passwd: # head /etc/passwd When multiple files are provided, head shows the first ten lines of each file. Use -n with a number to specify a different line count, e.g., # head -n5 /var/log/yum.log shows the first five lines.

2. tail command

The tail command displays the last ten lines of a file by default. Syntax: tail [options] [filenames]. Example to show the last ten lines of /etc/passwd: # tail /etc/passwd Like head, it works with multiple files. Use -n to change the number of lines, e.g., # tail -n20 /var/log/yum.log. The -f option follows a file in real time, useful for logs: # tail -f /var/log/messages.

3. more command

The more command pages through a file one screen at a time. Syntax: more [options] [filenames]. Example: # more /var/log/messages Press Enter to scroll line by line, Space for the next page, and q to quit. Useful options include -num to set lines per page, +num to start at a specific line, and /pattern to search for a pattern.

4. less command

The less command also pages through files but allows both forward and backward navigation and searching. Syntax: less [options] [filenames]. Example: # less /var/log/messages Key controls: Space (down a page), b (up a page), j / k (line down/up), /pattern (search), n (next match), and q (quit). Options such as -num, +num, and /pattern work similarly to more.

5. Using less with pipelines

less

can view the output of other commands via a pipe, e.g., cat urls.txt | less, enabling paging through generated content.

6. cat command

The cat command concatenates and displays file contents. Syntax: cat [options] [filenames] [-] [filenames]. Basic usage to view a file: # cat /etc/passwd It can also combine multiple files: # cat 1 2 3 4 > 5, then display the combined file with # cat 5. Redirecting output creates new files, e.g., # cat > devops.txt. A here‑document can define custom end markers:

# cat > test.txt << end
I am Avishek
Here i am writing this post
Hope your are enjoying
end

Reading the created file: # cat test.txt Finally, cat can copy files: # cat name.txt > name1.txt and then view the copy.