cat <file>Display file contents
less <file>View file with pagination
head -n 20 <file>Show first 20 lines
tail -n 20 <file>Show last 20 lines
tail -f <file>Follow file changes in real-time
grep "pattern" <file>Search for pattern in file
grep -r "pattern" <dir>Search recursively in directory
grep -i "pattern" <file>Case-insensitive search
grep -c "pattern" <file>Count matching lines
sed "s/old/new/g" <file>Replace text in file
awk '{print $1}' <file>Print first column
sort <file>Sort lines alphabetically
sort -n <file>Sort lines numerically
uniqRemove adjacent duplicate lines
wc -l <file>Count lines in file
wc -w <file>Count words in file
cut -d"," -f1 <file>Extract column from delimited file
tr "a-z" "A-Z"Translate/replace characters
diff <file1> <file2>Compare two files