ed

Start an interactive editor session with an empty document

$ ed

$ ed [[-p|--prompt]] '[> ]'

$ ed [[-v|--verbose]]

$ ed [[-q|--quiet]] [[-s|--script]]

$ ed [[-l|--loose-exit-status]]

$ ed [path/to/file]

$ ,s/[regex]/[replacement]/g

$ q

ed [options] [file]

-G, --traditional
    Use POSIX basic regular expressions (BRE).

-s, --quiet, --silent
    Suppress diagnostics, byte counts, and '!' prompt.

-p string, --prompt=string
    Set editor prompt to string (default '?').

-l, --loose-exit-status
    Exit 0 unless fatal error, even on command failure.

-r, --restricted
    Restricted mode: no shell escapes or file writes outside original.

-S script, --script=script
    Execute commands from script file at startup.

-t tag, --tag=tag
    Jump to line with tag from 'tags' file.

-v, --version
    Print version information and exit.

-h, --help
    Print usage summary and exit.

ed is the original Unix text editor, a modal, line-oriented tool for editing text files via command line instructions. It operates on a buffer of numbered lines, using terse single-letter commands preceded by optional addresses (line numbers, ranges like 1,$, or patterns like /foo/). Default mode is command mode; enter input mode with a (append), i (insert), or c (change), exiting with a single dot . on a blank line.

Key commands: p (print), = (line number), n (line with number), d (delete), y (yank), u (undo), w (write file), q (quit), ! (shell escape), g/pat/cmd (global on pattern), v/pat/cmd (global not matching), s/old/new/ (substitute).

Ed reads files into memory, supports scripting for batch edits, and is POSIX-mandated. It's scriptable progenitor of sed and basis for ex/vi. Minimal footprint suits embedded systems; customizable prompt aids interaction. Type H for help, h for error explanation.

Terse syntax requires memorization; limited undo (single-level u); no visual feedback or syntax highlighting; modal nature confuses beginners; memory-limited for huge files; always w before q to avoid loss.

End append/insert/change with lone . on line.
H for full help; h explains errors.

., $ (last), % (all), /re/ (search forward), ?re? (backward); ranges like 5,10; 0 for before first.

Created by Ken Thompson in 1971 for 1st Edition Unix at Bell Labs. Standardized in POSIX.1; GNU ed by Antonio Diaz Diaz since 1999 adds extensions while preserving compatibility. Basis for ex (1976, Bill Joy) and vi.

sed(1), ex(1), vi(1), awk(1)