FILE SPACING:

double space a file

 sed G

double space a file which already has blank lines in it. Output file

should contain no more than one blank line between lines of text.

sed '/^$/d;G'

triple space a file

sed 'G;G'

undo double-spacing (assumes even-numbered lines are always blank)

 sed 'n;d'

insert a blank line above every line which matches “regex”

sed '/regex/{x;p;x;}'

insert a blank line below every line which matches “regex”

sed '/regex/G'

insert a blank line above and below every line which matches “regex”

sed '/regex/{x;p;x;G;}'

NUMBERING:

number each line of a file (simple left alignment). Using a tab

note on ‘\t’ at end of file) instead of space will preserve margins.

 sed = filename | sed 'N;s/\n/\t/'

number each line of a file (number on left, right-aligned)

sed = filename | sed 'N; s/^/ /; s/ *\(.\{6,\}\)\n/\1 /'

number each line of file, but only print numbers if line is not blank

sed '/./=' filename | sed '/./N; s/\n/ /'

count lines (emulates “wc -l”)

sed -n '$='

Text Conversion and Subsitution:

IN UNIX ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format

 sed 's/.$//' # assumes that all lines end with CR/LF
 sed 's/^M$//' # in bash/tcsh, press Ctrl-V then Ctrl-M
 sed 's/\x0D$//' # gsed 3.02.80, but top script is easier

IN UNIX ENVIRONMENT: convert Unix newlines (LF) to DOS format

 sed "s/$/`echo -e \\\r`/" # command line under ksh
 sed 's/$'"/`echo \\\r`/" # command line under bash
 sed "s/$/`echo \\\r`/" # command line under zsh
 sed 's/$/\r/' # gsed 3.02.80

IN DOS ENVIRONMENT: convert Unix newlines (LF) to DOS format

sed "s/$//" # method 1
 sed -n p # method 2

IN DOS ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format

Can only be done with UnxUtils sed, version 4.0.7 or higher.

Cannot be done with other DOS versions of sed. Use “tr” instead.

sed "s/\r//" infile >outfile # UnxUtils sed v4.0.7 or higher
 tr -d \r <infile >outfile # GNU tr version 1.22 or higher

delete leading whitespace (spaces, tabs) from front of each line

aligns all text flush left

sed 's/^[ \t]*//' # see note on '\t' at end of file

delete trailing whitespace (spaces, tabs) from end of each line

sed 's/[ \t]*$//' # see note on '\t' at end of file

delete BOTH leading and trailing whitespace from each line

sed 's/^[ \t]*//;s/[ \t]*$//'

insert 5 blank spaces at beginning of each line (make page offset)

sed 's/^/ /'

align all text flush right on a 79-column width

sed -e :a -e 's/^.\{1,78\}$/ &/;ta' # set at 78 plus 1 space

center all text in the middle of 79-column width. In method 1,

spaces at the beginning of the line are significant, and trailing

spaces are appended at the end of the line. In method 2, spaces at

the beginning of the line are discarded in centering the line, and

no trailing spaces appear at the end of lines.

sed -e :a -e 's/^.\{1,77\}$/ & /;ta' # method 1
 sed -e :a -e 's/^.\{1,77\}$/ &/;ta' -e 's/\( *\)\1/\1/' # method 2

substitute (find and replace) “foo” with “bar” on each line

sed 's/foo/bar/' # replaces only 1st instance in a line
 sed 's/foo/bar/4' # replaces only 4th instance in a line
 sed 's/foo/bar/g' # replaces ALL instances in a line
 sed 's/\(.*\)foo\(.*foo\)/\1bar\2/' # replace the next-to-last case
 sed 's/\(.*\)foo/\1bar/' # replace only the last case

substitute “foo” with “bar” ONLY for lines which contain “baz”

sed '/baz/s/foo/bar/g'

substitute “foo” with “bar” EXCEPT for lines which contain “baz”

sed '/baz/!s/foo/bar/g'

change “scarlet” or “ruby” or “puce” to “red”

sed 's/scarlet/red/g;s/ruby/red/g;s/puce/red/g' # most seds
sed 's/scarlet\|ruby\|puce/red/g' # GNU sed only

reverse order of lines (emulates “tac”)

bug/feature in HHsed v1.5 causes blank lines to be deleted

sed '1!G;h;$!d' # method 1
 sed -n '1!G;h;$p' # method 2

reverse each character on the line (emulates “rev”)

sed '/\n/!G;s/\(.\)\(.*\n\)/&\2\1/;//D;s/.//'

join pairs of lines side-by-side (like “paste”)

sed '$!N;s/\n/ /'

if a line ends with a backslash, append the next line to it

sed -e :a -e '/\\$/N; s/\\\n//; ta'

if a line begins with an equal sign, append it to the previous line

and replace the “=” with a single space

sed -e :a -e '$!N;s/\n=/ /;ta' -e 'P;D'

add commas to numeric strings, changing “1234567” to “1,234,567”

gsed ':a;s/\B[0-9]\{3\}\>/,&/;ta' # GNU sed
 sed -e :a -e 's/\(.*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta' # other seds

add commas to numbers with decimal points and minus signs (GNU sed)

gsed ':a;s/\(^\|[^0-9.]\)\([0-9]\+\)\([0-9]\{3\}\)/\1\2,\3/g;ta'

add a blank line every 5 lines (after lines 5, 10, 15, 20, etc.)

gsed '0~5G' # GNU sed only
 sed 'n;n;n;n;G;' # other seds

Selective Printing of Lines:

print first 10 lines of file (emulates behavior of “head”)

 sed 10q

print first line of file (emulates “head -1”)

sed q

print the last 10 lines of a file (emulates “tail”)

sed -e :a -e '$q;N;11,$D;ba'

print the last 2 lines of a file (emulates “tail -2”)

sed '$!N;$!D'

print the last line of a file (emulates “tail -1”)

sed '$!d' # method 1
 sed -n '$p' # method 2

print only lines which match regular expression (emulates “grep”)

sed -n '/regexp/p' # method 1
 sed '/regexp/!d' # method 2

print only lines which do NOT match regexp (emulates “grep -v”)

sed -n '/regexp/!p' # method 1, corresponds to above
 sed '/regexp/d' # method 2, simpler syntax

print the line immediately before a regexp, but not the line

containing the regexp

sed -n '/regexp/{g;1!p;};h'

print the line immediately after a regexp, but not the line

containing the regexp

sed -n '/regexp/{n;p;}'

print 1 line of context before and after regexp, with line number

indicating where the regexp occurred (similar to “grep -A1 -B1”)

sed -n -e '/regexp/{=;x;1!p;g;$!N;p;D;}' -e h

grep for AAA and BBB and CCC (in any order)

sed '/AAA/!d; /BBB/!d; /CCC/!d'

grep for AAA and BBB and CCC (in that order)

sed '/AAA.*BBB.*CCC/!d'

grep for AAA or BBB or CCC (emulates “egrep”)

sed -e '/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d # most se ds
 gsed '/AAA\|BBB\|CCC/!d' # GNU sed only

print paragraph if it contains AAA (blank lines separate paragraphs)

HHsed v1.5 must insert a ‘G;’ after ‘x;’ in the next 3 scripts below

sed -e '/./{H;$!d;}' -e 'x;/AAA/!d;'

print paragraph if it contains AAA and BBB and CCC (in any order)

sed -e '/./{H;$!d;}' -e 'x;/AAA/!d;/BBB/!d;/CCC/!d'

print paragraph if it contains AAA or BBB or CCC

sed -e '/./{H;$!d;}' -e 'x;/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d
 gsed '/./{H;$!d;};x;/AAA\|BBB\|CCC/b;d' # GNU sed only

print only lines of 65 characters or longer

sed -n '/^.\{65\}/p'

print only lines of less than 65 characters

sed -n '/^.\{65\}/!p' # method 1, corresponds to above
 sed '/^.\{65\}/d' # method 2, simpler syntax

print section of file from regular expression to end of file

sed -n '/regexp/,$p'

print section of file based on line numbers (lines 8-12, inclusive)

sed -n '8,12p' # method 1
 sed '8,12!d' # method 2

print line number 52

sed -n '52p' # method 1
 sed '52!d' # method 2
 sed '52q;d' # method 3, efficient on large files

beginning at line 3, print every 7th line

gsed -n '3~7p' # GNU sed only
 sed -n '3,${p;n;n;n;n;n;n;}' # other seds

print section of file between two regular expressions (inclusive)

sed -n '/Iowa/,/Montana/p' # case sensitive

Selective Deletion of Lines:

print all of file EXCEPT section between 2 regular expressions

sed '/Iowa/,/Montana/d'

delete duplicate, consecutive lines from a file (emulates “uniq”).

First line in a set of duplicate lines is kept, rest are deleted.

sed '$!N; /^\(.*\)\n\1$/!P; D'

delete duplicate, nonconsecutive lines from a file. Beware not to

overflow the buffer size of the hold space, or else use GNU sed.

sed -n 'G; s/\n/&&/; /^\([ -~]*\n\).*\n\1/d; s/\n//; h; P'

delete all lines except duplicate lines (emulates “uniq -d”).

sed '$!N; s/^\(.*\)\n\1$/\1/; t; D'

delete the first 10 lines of a file

sed '1,10d'

delete the last line of a file

sed '$d'

delete the last 2 lines of a file

sed 'N;$!P;$!D;$d'

delete the last 10 lines of a file

sed -e :a -e '$d;N;2,10ba' -e 'P;D' # method 1
 sed -n -e :a -e '1,10!{P;N;D;};N;ba' # method 2

delete every 8th line

gsed '0~8d' # GNU sed only
 sed 'n;n;n;n;n;n;n;d;' # other seds

delete ALL blank lines from a file (same as “grep ‘.’ “)

sed '/^$/d' # method 1
 sed '/./!d' # method 2

delete all CONSECUTIVE blank lines from file except the first; also

deletes all blank lines from top and end of file (emulates “cat -s”)

sed '/./,/^$/!d' # method 1, allows 0 blanks at top, 1 at EOF
 sed '/^$/N;/\n$/D' # method 2, allows 1 blank at top, 0 at EOF

delete all CONSECUTIVE blank lines from file except the first 2:

sed '/^$/N;/\n$/N;//D'

delete all leading blank lines at top of file

sed '/./,$!d'

delete all trailing blank lines at end of file

sed -e :a -e '/^\n*$/{$d;N;ba' -e '}' # works on all seds
 sed -e :a -e '/^\n*$/N;/\n$/ba' # ditto, except for gsed 3.02*

delete the last line of each paragraph

sed -n '/^$/{p;h;};/./{x;/./p;}'

Resources:

http://www.catonmat.net/blog/wp-content/uploads/2008/09/sed1line.txt