Sed

Check the APO unix pages for more.

NOTE!! On some systems you need the -E option to have possix Regular Expressions supported

Tricks

sed 's/\r//' filename > newfilename

dos2unix substitute, remove all DOS line endings.

sed -i 'commands' filename

Edit the file directly (inplace), by default the result is sent to standard output.

Basics

sed '/<pattern>/<action>' <file>

Execute action on all lines in <file> matching <pattern>

Simple actions are d(elete) (can be negated using !d, delete all lines not matching), p(rint), q(uit)

sed 's/<old_string>/<new_string>/g' <file>

Substitute, no whitespace is allowed after the command (s), the first character following s is the fieldseperator./g substitutes all matching patterns in a line. Use \n to insert a newline.

sed 's/pattern(with)sub(patterns)/\1 newpartofstring \2/' <file>

\1 and \2 refer to the subpatterns between brackets ().

sed '/<pattern>/[ia]<text>'

i inserts <text> before the matched line, a after the line

sed '/<pattern>/[rw] <file>'

r(ead) from or w(rite) to <file> if <pattern> is matched.