Linux Basics: File Viewing and Management Commands

touch [options] <file>

touch file.txt                    # Create an empty file
touch file1.txt file2.txt         # Create multiple files
touch existing.txt                # Update timestamps
touch file{1..5}.txt              # Create file1.txt ~ file5.txt

touch -a file.txt                 # Update access time (atime)
touch -m file.txt                 # Update modification time (mtime)
touch -c file.txt                 # Do not create the file if it doesn't exist
touch -d "2026-07-04 12:30:00" file.txt
touch -t 202607041230 file.txt
touch -r source.txt target.txt    # Copy timestamps from another file

stat file.txt

cat [options] <file>

cat file.txt
cat file1.txt file2.txt
cat file1.txt file2.txt > combined.txt

cat > new_file.txt        # Create or overwrite
cat >> file.txt           # Append to an existing file

cat -n file.txt           # Show line numbers
cat -b file.txt           # Number non-empty lines only
cat -s file.txt           # Squeeze multiple blank lines
cat -E file.txt           # Show end-of-line markers ($)
cat -A file.txt           # Show all non-printing characters

head file.txt
tail file.txt
less file.txt

less file.txt

q

/keyword      Search forward
?keyword      Search backward
n             Next match
N             Previous match

less -N app.log           # Show line numbers
less -i app.log           # Case-insensitive search
less +F app.log           # Follow file like tail -f
ps -ef | less             # View command output page by page

head [options] <file>

head file.txt
head -n 5 file.txt
head -5 file.txt
head -c 20 file.txt

head -q file1.txt file2.txt     # Hide file headers
head -v file.txt                # Always show file header

head -n 15 system.log | tail -n 5

ls -lt | head -n 6

tail [options] <file>

tail file.txt
tail -n 5 file.txt
tail -5 file.txt
tail -n +20 file.txt

tail -f app.log              # Follow file updates
tail -F app.log              # Continue following after log rotation
tail -f app.log --pid=1234   # Stop when process exits

tail -n 30 file.txt
tail -c 100 file.txt

tail -f app.log | grep "ERROR"