psed.1

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.RS 4
.IP "\fBg\fR" 8
.IX Item "g"
The replacement is performed for all matching, non-overlapping substrings
of the pattern space.
.IP "\fB1\fR..\fB9\fR" 8
.IX Item "1..9"
Replace only the n\-th matching substring of the pattern space.
.IP "\fBp\fR" 8
.IX Item "p"
If the substitution was made, print the new value of the pattern space.
.IP "\fBw\fR \fIfile\fR" 8
.IX Item "w file"
If the substitution was made, write the new value of the pattern space
to the specified file.
.RE
.RS 4
.RE
.IP "[2addr]\fBt\fR [\fIlabel\fR]" 4
.IX Item "[2addr]t [label]"
Branch to the \fB:\fR function with the specified \fIlabel\fR if any \fBs\fR
substitutions have been made since the most recent reading of an input line
or execution of a \fBt\fR function. If no label is given, branch to the end of
the script.
.IP "[2addr]\fBw\fR \fIfile\fR" 4
.IX Item "[2addr]w file"
The contents of the pattern space are written to the \fIfile\fR.
.IP "[2addr]\fBx\fR" 4
.IX Item "[2addr]x"
Swap the contents of the pattern space and the hold space.
.IP "[2addr]\fBy\fR\fB/\fR\fIstring1\fR\fB/\fR\fIstring2\fR\fB/\fR" 4
.IX Item "[2addr]y/string1/string2/"
In the pattern space, replace all characters occuring in \fIstring1\fR by the
character at the corresponding position in \fIstring2\fR. It is possible
to use any character (other than a backslash or newline) instead of a
slash to delimit the strings.  Within \fIstring1\fR and \fIstring2\fR, a
backslash followed by any character other than a newline is that literal
character, and a backslash followed by an `n' is replaced by a newline
character.
.IP "[1addr]\fB=\fR" 4
.IX Item "[1addr]="
Prints the current line number on the standard output.
.IP "[0addr]\fB:\fR [\fIlabel\fR]" 4
.IX Item "[0addr]: [label]"
The command specifies the position of the \fIlabel\fR. It has no other effect.
.IP "[2addr]\fB{\fR [\fIcommand\fR]" 4
.IX Item "[2addr]{ [command]"
.PD 0
.IP "[0addr]\fB}\fR" 4
.IX Item "[0addr]}"
.PD
These two commands begin and end a command list. The first command may
be given on the same line as the opening \fB{\fR command. The commands
within the list are jointly selected by the address(es) given on the
\&\fB{\fR command (but may still have individual addresses).
.IP "[0addr]\fB#\fR [\fIcomment\fR]" 4
.IX Item "[0addr]# [comment]"
The entire line is ignored (treated as a comment). If, however, the first
two characters in the script are `\f(CW\*(C`#n\*(C'\fR', automatic printing of output is
suppressed, as if the \fB\-n\fR option were given on the command line.
.SH "BASIC REGULAR EXPRESSIONS"
.IX Header "BASIC REGULAR EXPRESSIONS"
A \fIBasic Regular Expression\fR (\s-1BRE\s0), as defined in \s-1POSIX\s0 1003.2, consists
of \fIatoms\fR, for matching parts of a string, and \fIbounds\fR, specifying
repetitions of a preceding atom.
.Sh "Atoms"
.IX Subsection "Atoms"
The possible atoms of a \s-1BRE\s0 are: \fB.\fR, matching any single character;
\&\fB^\fR and \fB$\fR, matching the null string at the beginning or end
of a string, respectively; a \fIbracket expressions\fR, enclosed
in \fB[\fR and \fB]\fR (see below); and any single character with no
other significance (matching that character). A \fB\e\fR before one
of: \fB.\fR, \fB^\fR, \fB$\fR, \fB[\fR, \fB*\fR, \fB\e\fR, matching the character
after the backslash. A sequence of atoms enclosed in \fB\e(\fR and \fB\e)\fR
becomes an atom and establishes the target for a \fIbackreference\fR,
consisting of the substring that actually matches the enclosed atoms.
Finally, \fB\e\fR followed by one of the digits \fB0\fR through \fB9\fR is a
backreference.
.PP
A \fB^\fR that is not first, or a \fB$\fR that is not last does not have
a special significance and need not be preceded by a backslash to
become literal. The same is true for a \fB]\fR, that does not terminate
a bracket expression.
.PP
An unescaped backslash cannot be last in a \s-1BRE\s0.
.Sh "Bounds"
.IX Subsection "Bounds"
The \s-1BRE\s0 bounds are: \fB*\fR, specifying 0 or more matches of the preceding
atom; \fB\e{\fR\fIcount\fR\fB\e}\fR, specifying that many repetitions;
\&\fB\e{\fR\fIminimum\fR\fB,\e}\fR, giving a lower limit; and
\&\fB\e{\fR\fIminimum\fR\fB,\fR\fImaximum\fR\fB\e}\fR finally defines a lower and upper
bound.
.PP
A bound appearing as the first item in a \s-1BRE\s0 is taken literally.
.Sh "Bracket Expressions"
.IX Subsection "Bracket Expressions"
A \fIbracket expression\fR is a list of characters, character ranges
and character classes enclosed in \fB[\fR and \fB]\fR and matches any
single character from the represented set of characters.
.PP
A character range is written as two characters separated by \fB\-\fR and
represents all characters (according to the character collating sequence)
that are not less than the first and not greater than the second.
(Ranges are very collating-sequence-dependent, and portable programs
should avoid relying on them.)
.PP
A character class is one of the class names
.PP
.Vb 4
\&   alnum     digit     punct
\&   alpha     graph     space
\&   blank     lower     upper
\&   cntrl     print     xdigit
.Ve
.PP
enclosed in \fB[:\fR and \fB:]\fR and represents the set of characters
as defined in \fIctype\fR\|(3).
.PP
If the first character after \fB[\fR is \fB^\fR, the sense of matching is
inverted.
.PP
To include a literal `\f(CW\*(C`^\*(C'\fR', place it anywhere else but first. To
include a literal '\f(CW\*(C`]\*(C'\fR' place it first or immediately after an
initial \fB^\fR. To include a literal `\f(CW\*(C`\-\*(C'\fR' make it the first (or
second after \fB^\fR) or last character, or the second endpoint of
a range.
.PP
The special bracket expression constructs \f(CW\*(C`[[:<:]]\*(C'\fR and \f(CW\*(C`[[:>:]]\*(C'\fR 
match the null string at the beginning and end of a word respectively.
(Note that neither is identical to Perl's `\eb' atom.)
.Sh "Additional Atoms"
.IX Subsection "Additional Atoms"
Since some sed implementations provide additional regular expression
atoms (not defined in \s-1POSIX\s0 1003.2), \fBpsed\fR is capable of translating
the following backslash escapes:
.ie n .IP "\fB\e<\fR This is the same as ""[[:>:]]""." 4
.el .IP "\fB\e<\fR This is the same as \f(CW[[:>:]]\fR." 4
.IX Item "< This is the same as [[:>:]]."
.PD 0
.ie n .IP "\fB\e>\fR This is the same as ""[[:<:]]""." 4
.el .IP "\fB\e>\fR This is the same as \f(CW[[:<:]]\fR." 4
.IX Item "> This is the same as [[:<:]]."
.ie n .IP "\fB\ew\fR This is an abbreviation for ""[[:alnum:]_]""." 4
.el .IP "\fB\ew\fR This is an abbreviation for \f(CW[[:alnum:]_]\fR." 4
.IX Item "w This is an abbreviation for [[:alnum:]_]."
.ie n .IP "\fB\eW\fR This is an abbreviation for ""[^[:alnum:]_]""." 4
.el .IP "\fB\eW\fR This is an abbreviation for \f(CW[^[:alnum:]_]\fR." 4
.IX Item "W This is an abbreviation for [^[:alnum:]_]."
.IP "\fB\ey\fR Match the empty string at a word boundary." 4
.IX Item "y Match the empty string at a word boundary."
.IP "\fB\eB\fR Match the empty string between any two either word or non-word characters." 4
.IX Item "B Match the empty string between any two either word or non-word characters."
.PD
.PP
To enable this feature, the environment variable \s-1PSEDEXTBRE\s0 must be set
to a string containing the requested characters, e.g.:
\&\f(CW\*(C`PSEDEXTBRE=\*(Aq<>wW\*(Aq\*(C'\fR.
.SH "ENVIRONMENT"
.IX Header "ENVIRONMENT"
The environment variable \f(CW\*(C`PSEDEXTBRE\*(C'\fR may be set to extend BREs.
See \*(L"Additional Atoms\*(R".
.SH "DIAGNOSTICS"
.IX Header "DIAGNOSTICS"
.IP "ambiguous translation for character `%s' in `y' command" 4
.IX Item "ambiguous translation for character `%s' in `y' command"
The indicated character appears twice, with different translations.
.IP "`[' cannot be last in pattern" 4
.IX Item "`[' cannot be last in pattern"
A `[' in a \s-1BRE\s0 indicates the beginning of a \fIbracket expression\fR.
.IP "`\e' cannot be last in pattern" 4
.IX Item "`' cannot be last in pattern"
A `\e' in a \s-1BRE\s0 is used to make the subsequent character literal.
.IP "`\e' cannot be last in substitution" 4
.IX Item "`' cannot be last in substitution"
A `\e' in a subsitution string is used to make the subsequent character literal.
.IP "conflicting flags `%s'" 4
.IX Item "conflicting flags `%s'"
In an \fBs\fR command, either the `g' flag and an n\-th occurrence flag, or
multiple n\-th occurrence flags are specified. Note that only the digits
`1' through `9' are permitted.
.ie n .IP "duplicate label %s\fR (first defined at \f(CW%s)" 4
.el .IP "duplicate label \f(CW%s\fR (first defined at \f(CW%s\fR)" 4
.IX Item "duplicate label %s (first defined at %s)"
.PD 0
.IP "excess address(es)" 4
.IX Item "excess address(es)"
.PD
The command has more than the permitted number of addresses.
.IP "extra characters after command (%s)" 4
.IX Item "extra characters after command (%s)"
.PD 0
.IP "illegal option `%s'" 4
.IX Item "illegal option `%s'"
.IP "improper delimiter in s command" 4
.IX Item "improper delimiter in s command"
.PD
The \s-1BRE\s0 and substitution may not be delimited with `\e' or newline.
.IP "invalid address after `,'" 4
.IX Item "invalid address after `,'"
.PD 0
.IP "invalid backreference (%s)" 4
.IX Item "invalid backreference (%s)"
.PD
The specified backreference number exceeds the number of backreferences
in the \s-1BRE\s0.
.IP "invalid repeat clause `\e{%s\e}'" 4
.IX Item "invalid repeat clause `{%s}'"
The repeat clause does not contain a valid integer value, or pair of
values.
.IP "malformed regex, 1st address" 4
.IX Item "malformed regex, 1st address"
.PD 0
.IP "malformed regex, 2nd address" 4
.IX Item "malformed regex, 2nd address"
.IP "malformed regular expression" 4
.IX Item "malformed regular expression"
.IP "malformed substitution expression" 4
.IX Item "malformed substitution expression"
.IP "malformed `y' command argument" 4
.IX Item "malformed `y' command argument"
.PD
The first or second string of a \fBy\fR command  is syntactically incorrect.
.IP "maximum less than minimum in `\e{%s\e}'" 4
.IX Item "maximum less than minimum in `{%s}'"
.PD 0
.IP "no script command given" 4
.IX Item "no script command given"
.PD
There must be at least one \fB\-e\fR or one \fB\-f\fR option specifying a
script or script file.
.IP "`\e' not valid as delimiter in `y' command" 4
.IX Item "`' not valid as delimiter in `y' command"
.PD 0
.IP "option \-e requires an argument" 4
.IX Item "option -e requires an argument"
.IP "option \-f requires an argument" 4
.IX Item "option -f requires an argument"
.IP "`s' command requires argument" 4
.IX Item "`s' command requires argument"
.IP "start of unterminated `{'" 4
.IX Item "start of unterminated `{'"
.IP "string lengths in `y' command differ" 4
.IX Item "string lengths in `y' command differ"
.PD
The translation table strings in a \fBy\fR command must have equal lengths.
.IP "undefined label `%s'" 4
.IX Item "undefined label `%s'"
.PD 0
.IP "unexpected `}'" 4
.IX Item "unexpected `}'"
.PD
A \fB}\fR command without a preceding \fB{\fR command was encountered.
.IP "unexpected end of script" 4
.IX Item "unexpected end of script"
The end of the script was reached although a text line after a
\&\fBa\fR, \fBc\fR or \fBi\fR command indicated another line.
.IP "unknown command `%s'" 4
.IX Item "unknown command `%s'"
.PD 0
.IP "unterminated `['" 4
.IX Item "unterminated `['"
.PD
A \s-1BRE\s0 contains an unterminated bracket expression.
.IP "unterminated `\e('" 4
.IX Item "unterminated `('"
A \s-1BRE\s0 contains an unterminated backreference.
.IP "`\e{' without closing `\e}'" 4
.IX Item "`{' without closing `}'"
A \s-1BRE\s0 contains an unterminated bounds specification.
.IP "`\e)' without preceding `\e('" 4
.IX Item "`)' without preceding `('"
.PD 0
.IP "`y' command requires argument" 4
.IX Item "`y' command requires argument"
.PD
.SH "EXAMPLE"
.IX Header "EXAMPLE"
The basic material for the preceding section was generated by running
the sed script
.PP
.Vb 10
\&   #no autoprint
\&   s/^.*Warn( *"\e([^"]*\e)".*$/\e1/
\&   t process
\&   b
\&   :process
\&   s/$!/%s/g
\&   s/$[_[:alnum:]]\e{1,\e}/%s/g
\&   s/\e\e\e\e/\e\e/g
\&   s/^/=item /
\&   p
.Ve
.PP
on the program's own text, and piping the output into \f(CW\*(C`sort \-u\*(C'\fR.
.SH "SED SCRIPT TRANSLATION"
.IX Header "SED SCRIPT TRANSLATION"
If this program is invoked with the name \fIs2p\fR it will act as a
sed-to-Perl translator. After option processing (all other
arguments are ignored), a Perl program is printed on standard
output, which will process the input stream (as read from all
arguments) in the way defined by the sed script and the option setting
used for the translation.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIperl\fR\|(1), \fIre_format\fR\|(7)
.SH "BUGS"
.IX Header "BUGS"
The \fBl\fR command will show escape characters (\s-1ESC\s0) as `\f(CW\*(C`\ee\*(C'\fR', but
a vertical tab (\s-1VT\s0) in octal.
.PP
Trailing spaces are truncated from labels in \fB:\fR, \fBt\fR and \fBb\fR commands.
.PP
The meaning of an empty regular expression (`\f(CW\*(C`//\*(C'\fR'), as defined by \fBsed\fR,
is \*(L"the last pattern used, at run time\*(R". This deviates from the Perl
interpretation, which will re-use the \*(L"last last successfully executed
regular expression\*(R". Since keeping track of pattern usage would create
terribly cluttered code, and differences would only appear in obscure
context (where other \fBsed\fR implementations appear to deviate, too),
the Perl semantics was adopted. Note that common usage of this feature,
such as in \f(CW\*(C`/abc/s//xyz/\*(C'\fR, will work as expected.
.PP
Collating elements (of bracket expressions in BREs) are not implemented.
.SH "STANDARDS"
.IX Header "STANDARDS"
This \fBsed\fR implementation conforms to the \s-1IEEE\s0 Std1003.2\-1992 (\*(L"\s-1POSIX\s0.2\*(R")
definition of \fBsed\fR, and is compatible with the \fIOpenBSD\fR
implementation, except where otherwise noted (see \*(L"\s-1BUGS\s0\*(R").
.SH "AUTHOR"
.IX Header "AUTHOR"
This Perl implementation of \fIsed\fR was written by Wolfgang Laun,
\&\[e-mail]\fR.
.SH "COPYRIGHT and LICENSE"
.IX Header "COPYRIGHT and LICENSE"
This program is free and open software. You may use, modify,
distribute, and sell this program (and any modified variants) in any
way you wish, provided you do not restrict others from doing the same.