Viewing files cheat sheet
The most useful viewing files commands on one printable page, every line checked by running it.
cat Concatenate files and print them to standard output; also the quickest way to see a short file.
$ cat todo.txt- Print a short file output
$ cat logs/app.log.1 logs/error.log- Join several files into one stream output
$ cat -n notes.txt- Number every line output
$ cat -A data/windows.txt- Reveal Windows line endings output
head Print the first lines (or bytes) of files; 10 lines by default.
$ head -n 3 data/users.csv- Choose how many lines output
$ head -n -3 todo.txt- Everything except the last lines output
$ cut -d ' ' -f 1 access.log | sort | uniq -c | sort -rn | head -n 3- Keep the top results of a pipeline output
hexdump Display file contents in hex, octal, decimal or ASCII, with a canonical hex-plus-text layout via -C.
$ hexdump -C data/windows.txt- Hex and text side by side output
$ hexdump -C -n 16 photos/beach.png- Only the first bytes output
less Page through a file or command output one screen at a time, with search and scrolling in both directions.
$ grep -n INFO logs/app.log | less- Page the output of another command output
$ less -F -X notes.txt- Skip the pager when the text fits on one screen output
nl Print files with line numbers added, with control over which lines get numbered and how.
$ nl todo.txt- Number the lines of a file output
$ nl -b a data/settings.conf- Number every line, including blank ones output
$ nl -w 2 -s '. ' todo.txt- Narrow numbers with a custom separator output
od Dump a file's bytes as octal, hex, decimal or characters, to see exactly what it contains.
$ od -c data/windows.txt- See every byte as a character output
$ od -An -t x1 todo.txt | head -n 2- Hex bytes without offsets output
$ od -A d -t x1z -N 32 photos/beach.png- Hex next to printable text output
tac Print files with their lines in reverse order, last line first.
$ tac todo.txt- Reverse the order of lines output
$ tac logs/app.log | head -n 3- Show the newest log entries first output
tail Print the last lines of files, or follow a file as it grows with -f.
$ tail -n 3 access.log- Choose how many lines output
$ tail -n +2 data/users.csv | head -n 3- Skip a header line output
$ (sleep 1; echo 'line added 1s later' >> logs/app.log) &
> timeout 3 tail -n 2 -f logs/app.log
> echo "tail stopped with status $?"- Follow a file as it grows output
$ tail -F /var/log/nginx/access.log- Keep following across log rotation output
wc Count lines, words, characters and bytes in files or standard input.
$ wc -l access.log- Count lines output
$ count=$(wc -l < todo.txt)
> echo "There are $count items to do"- Get just the number, for a script output
$ grep -c . access.log; grep ' 404 ' access.log | wc -l- Count the results of a pipeline output
xxd Make a hex dump of a file, or turn a hex dump back into binary with -r.
$ xxd -l 32 photos/beach.png- Hex dump of the start of a file output
$ xxd -p -l 16 README.md- Plain hex string output
$ echo 48656c6c6f2c20776f726c640a | xxd -r -p- Turn a hex string back into bytes output
From https://opscape.vip/cheatsheets/viewing/ · checked 2026-10-31
