Usage | Options | Commands | Expressions | Addresses
SED Regular Expressions
sed supports the basic regular expressions described on
the regexp(5) manual page, with the following additions:
\cREc
In a context address, the construction \cREc,
where c is any character other than a backslash or NEWLINE character, is
identical to /RE/. If the character designated by c appears following a
backslash, then it is considered to be that literal character, which does
not terminate the RE. For example, in the context address \xabc\xdefx,
the second x stands for itself, so that the regular expression is abcxdef.
\n
The escape sequence \n matches a NEWLINE character
embedded in the pattern space. A literal NEWLINE character must not be
used in the regular expression of a context address or in the substitute
command.
Editing commands can be applied only to non-selected
pattern spaces by use of the negation command ! (described below).
sed Editing Commands
In the following list of functions the maximum number
of permissible addresses for each function is indicated.
The r and w commands take an optional rfile (or wfile)
parameter, separated from the command letter by one or more blank characters.
Multiple commands can be specified by separating them
with a semicolon (;) on the same command line.
The text argument consists of one or more lines, all but
the last of which end with \ to hide the NEWLINE. Each embedded NEWLINE
character in the text must be preceded by a backslash. Other backslashes
in text are removed and the following character is treated literally. Backslashes
in text are treated like backslashes in the replacement string of an s
command, and may be used to protect initial blanks and tabs against the
stripping that is done on every script line.
The rfile or wfile argument must terminate the command
line and must be preceded by exactly one blank. The use of the wfile parameter
causes that file to be initially created, if it does not exist, or will
replace the contents of an existing file. There can be at most 10 distinct
wfile arguments.
Regular expressions match entire strings, not just individual
lines, but a NEWLINE character is matched by \n in a sed RE; a NEWLINE
character is not allowed in an RE. Also note that \n cannot be used to
match a NEWLINE character at the end of an input line; NEWLINE characters
appear in the pattern space as a result of the N editing command.
Two of the commands take a command-list, which is a list
of sed commands separated by NEWLINE characters, as follows:
{ command command }
The { can be preceded with blank characters and can be
fol-lowed with white space. The commands can be preceded by white space.
The terminating } must be preceded by a NEW-LINE character and can be preceded
or followed by <blank>s. The braces may be preceded or followed by <blank>s.
The command may be preceeded by <blank>s, but may not be followed by
<blank>s.
The following table lists the functions, with the maximum
number of permissible addresses.
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