Sed Quick Reference

Generic command format:

[address]command

command = d, a, i, c, r, w, q, ... d: Delete. a: Append. i: Insert. c: Change. r: Read. w: Write. q: Quit.

Group command format:

address{
command1
command2
command3
}

Substitution format:

[address]s/pattern/replacement/flags

flags = n, g, p, or w file. n: A number n represents nth occurrence. g: Global. p: Print. w file: Write to file.

Transform format:

[address]y/abc/xyz/

Translate a->x, b->y, and c->z.

[address] can be lines found by regular expression matches, range of lines.

s/abc/xyz/p	Replace abc by xyz, and print (required 'p' if we use "sed -n" to suppress printing all lines).
s/abc/pqr/ s/pqr/xyz/	Replace abc by pqr, then replace pqr by xyz. Effectively, abc and pqr becomes xyz.
/abc/s/pqr/xyz/g	Find lines with abc, then replace pqr in the line by xyz. 'g' -> Replaces all pqr in the line.
1d	Deletes the first line.
$d	Deletes the last line.
/^$/d	Deletes blank lines.
3,10d	Deletes line 3 to line 10 inclusive.
3,10!d	Deletes all lines except line 3 to line 10 inclusive.
10,$d	Deletes line 10 to last line inclusive.
\(abc\)\+	Match one or more abc. Regular expression needs '\'.
abc+	Match literal abc+.
# A comment	Comment.
s!abc!xyz!	Replace abc by xyz, but using ! as delimiter.
a\abc	Append abc to the matching line.
i\abc	Insert abc before the matching line.
c\abc	Change the matching line to abc.
=	Print line with line number.
n	Output the contents of the pattern space and read next line.
r file	Read file.
w file	Write file.
&	Represent the regular expression matching string (used in replacement string).
\3	Match 3th substring in the regular expression using \( \).
s/\(a\)\(b\)/\2\1/	Replace ab by ba.
s/abc/xyz/2	Replace the 2nd abc by xyz.

There are other commands like multi-line commands (N, D, P), copying/appending pattern space to hold space vice versa (h,H,g,G,x), label(:labelname), branch to label (b), conditional branch (t).

Reference: UNIX Power Tools: sed & awk by Dale Dougherty