sed command help

 sed - a Stream EDitor
 

SYNOPSIS

 sed [-n] [-V] [--quiet] [--silent] [--version] [--help]
 [-e script] [--expression=script]
 [-f script-file] [--file=script-file]
 [script-if-no-other-script]
 [file...]
 

DESCRIPTION

 Sed is a stream editor. A stream editor is used to perュ
 form basic text transformations on an input stream (a file
 or input from a pipeline). While in some ways similar to
 an editor which permits scripted edits (such as ed), sed
 works by making only one pass over the input(s), and is
 consequently more efficient. But it is sed's ability to
 filter text in a pipeline which particularly distinguishes
 it from other types of editors.
 

OPTIONS

 Sed may be invoked with the following command-line
 options:
 
 -V
 
 --version
 Print out the version of sed that is being run and
 a copyright notice, then exit.
 
 -h
 
 --help Print a usage message briefly summarizing these
 command-line options and the bug-reporting address,
 then exit.
 
 -n
 
 --quiet
 
 --silent
 By default, sed will print out the pattern space at
 the end of each cycle through the script. These
 options disable this automatic printing, and sed
 will only produce output when explicitly told to
 via the p command.
 
 -e script
 
 --expression=script
 Add the commands in script to the set of commands
 to be run while processing the input.
 
 --file=script-file
 Add the commands contained in the file script-file
 to the set of commands to be run while processing
 the input.
 
 If no -e,-f,--expression, or --file options are given on
 the command-line, then the first non-option argument on
 the command line is taken to be the script to be executed.
 
 If any command-line parameters remain after processing the
 above, these parameters are interpreted as the names of
 input files to be processed. A file name of - refers to
 the standard input stream. The standard input will proュ
 cessed if no file names are specified.
 

Command Synopsis

 This is just a brief synopsis of sed commands to serve as
 a reminder to those who already know sed; other documentaュ
 tion (such as the texinfo document) must be consulted for
 fuller descriptions.
 
 Zero-address ``commands''
 : label
 Label for b and t commands.
 
 #comment
 The comment extends until the next newline (or the
 end of a -e script fragment).
 
 } The closing bracket of a { } block.
 
 Zero- or One- address commands
 = Print the current line number.
 
 a \
 
 text Append text, which has each embedded newline preュ
 ceeded by a backslash.
 
 i \
 
 text Insert text, which has each embedded newline preュ
 ceeded by a backslash.
 
 q Immediately quit the sed script without processing
 any more input, except that if auto-print is not
 diabled the current pattern space will be printed.
 
 r filename
 Append text read from filename.
 
 { Begin a block of commands (end with a }).
 
 b label
 Branch to label; if label is omitted, branch to end
 of script.
 
 t label
 If a s/// has done a successful substitution since
 the last input line was read and since the last t
 command, then branch to label; if label is omitted,
 branch to end of script.
 
 c \
 
 text Replace the selected lines with text, which has
 each embedded newline preceeded by a backslash.
 
 d Delete pattern space. Start next cycle.
 
 D Delete up to the first embedded newline in the patュ
 tern space. Start next cycle, but skip reading
 from the input if there is still data in the patュ
 tern space.
 
 h H Copy/append pattern space to hold space.
 
 g G Copy/append hold space to pattern space.
 
 x Exchange the contents of the hold and pattern
 spaces.
 
 l List out the current line in a ``visually unambiguュ
 ous'' form.
 
 n N Read/append the next line of input into the pattern
 space.
 
 p Print the current pattern space.
 
 P Print up to the first embedded newline of the curュ
 rent pattern space.
 
 s/regexp/replacement/
 Attempt to match regexp against the pattern space.
 If successful, replace that portion matched with
 replacement. The replacement may contain the speュ
 cial character & to refer to that portion of the
 pattern space which matched, and the special
 escapes 1円 through 9円 to refer to the corresponding
 matching sub-expressions in the regexp.
 
 w filename Write the current pattern space to fileュ
 Transliterate the characters in the pattern space
 which appear in source to the corresponding characュ
 ter in dest.
 

Addresses

 Sed commands can be given with no addresses, in which case
 the command will be executed for all input lines; with one
 address, in which case the command will only be executed
 for input lines which match that address; or with two
 addresses, in which case the command will be executed for
 all input lines which match the inclusive range of lines
 starting from the first address and continuing to the secュ
 ond address. Three things to note about address ranges:
 the syntax is addr1,addr2 (i.e., the addresses are sepaュ
 rated by a comma); the line which addr1 matched will
 always be accepted, even if addr2 selects an earlier line;
 and if addr2 is a regexp, it will not be tested against
 the line that addr1 matched.
 
 After the address (or address-range), and before the comュ
 mand, a ! may be inserted, which specifies that the comュ
 mand shall only be executed if the address (or address-
 range) does not match.
 
 The following address types are supported:
 
 number Match only the specified line number.
 
 first~step
 Match every step'th line starting with line first.
 For example, ``sed -n 1~2p'' will print all the
 odd-numbered lines in the input stream, and the
 address 2~5 will match every fifth line, starting
 with the second. (This is a GNU extension.)
 
 $ Match the last line.
 
 /regexp/
 Match lines matching the regular expression regexp.
 
 \cregexpc
 Match lines matching the regular expression regexp.
 The c may be any character.
 

Regular expressions

 POSIX.2 BREs should be supported, but they aren't comュ
 pletely yet. The \n sequence in a regular expression
 matches the newline character. There are also some GNU
 extensions. [XXX FIXME: more needs to be said. At the
 very least, a reference to another document which
 describes what is supported should be given.]
 
 This version of sed supports a \<newline> sequence in all
 regular expressions, the replacement part of a substitute
 (s) command, and in the source and dest parts of a
 transliterate (y) command. The \ is stripped, and the
 newline is kept.
 

SEE ALSO

 awk(1) , ed(1) , expr(1) , emacs(1) , perl(1) , tr(1) , vi(1) ,
 regex(5)  [well, one ought to be written... XXX], sed.info,
 any of various books on sed, the sed FAQ
 (http://www.wollery.demon.co.uk/sedtut10.txt,
 http://www.ptug.org/sed/sedfaq.htm).
 

BUGS

 E-mail bug reports to bug-gnu-utils@gnu.org. Be sure to
 include the word ``sed'' somewhere in the ``Subject:''
 field.