Text Processing

Command	Description
`cat file`	Display file with line numbers
`head [-n N] file`	Show first N lines (default 10)
`tail [-n N] file`	Show last N lines (default 10)
`grep [flags] pattern [files]`	Search files for pattern
`sort [-r/-n/-u] file`	Sort lines
`uniq [-c/-d] file`	Remove consecutive duplicate lines
`wc [-l/-w/-c] file`	Count lines, words, or characters
`diff file1 file2`	Compare two files
`tr [-d] s1 s2 file`	Translate or delete characters
`cut -d/-f/-c file`	Extract fields or characters
`rev file`	Reverse characters in each line
`tac file`	Print file with lines in reverse order
`paste [-d] file file`	Merge lines from multiple files
`more/less`	Paginated output viewer

grep

Search for patterns in files with highlighted matches. Supports recursive search, case-insensitive matching, line numbers, and match counting.

Shell

> grep -rn "TODO" src/
src/Parser.cs:42:    // TODO: Handle forward references
src/Interpreter.cs:156:    // TODO: Optimize stack layout

> grep -ic "error" logs/
logs/app.log:15
logs/server.log:3

Flags: -i case insensitive, -n line numbers, -r recursive, -c count only.

sort

Shell

> sort -r names.txt
Zara
Mike
Alice