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Diff for /src/usr.bin/awk/awk.1 between version 1.17 and 1.18

version 1.17, 2003/12/16 11:18:37 version 1.18, 2003/12/18 20:22:51
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 .Op Fl F Ar fs  .Op Fl F Ar fs
 .Oo Fl v Ar var Ns =  .Oo Fl v Ar var Ns =
 .Ns Ar value Oc  .Ns Ar value Oc
 .Ar prog | Fl f Ar progfile  .Op Ar prog | Fl f Ar progfile
 .Ar  .Ar
 .Nm nawk  .Nm nawk
 .Ar ...  .Ar ...
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 .Pc  .Pc
 and access to the environment  and access to the environment
 .Pf ( Va ENVIRON ;  .Pf ( Va ENVIRON ;
 see  see the section on variables below).
 .Sx VARIABLES  
 below).  
 This is a first  This is a first
 .Pq and not very reliable  .Pq and not very reliable
 approximation to a  approximation to a
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 options may be present.  options may be present.
 .El  .El
 .Pp  .Pp
   The input is normally made up of input lines
   .Pq records
   separated by newlines, or by the value of
   .Va RS .
   If
   .Va RS
   is null, then any number of blank lines are used as the record separator,
   and newlines are used as field separators
   (in addition to the value of
   .Va FS ) .
   This is convenient when working with multi-line records.
   .Pp
 An input line is normally made up of fields separated by whitespace,  An input line is normally made up of fields separated by whitespace,
 or by regular expression  or by the regular expression
 .Va FS .  .Va FS .
 The fields are denoted  The fields are denoted
 .Va $1 , $2 , ... ,  .Va $1 , $2 , ... ,
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 .Va FS  .Va FS
 is null, the input line is split into one field per character.  is null, the input line is split into one field per character.
 .Pp  .Pp
   Normally, any number of blanks separate fields.
   In order to set the field separator to a single blank, use the
   .Fl F
   option with a value of
   .Sq [\ \&] .
   If a field separator of
   .Sq t
   is specified,
   .Nm
   treats it as if
   .Sq \et
   had been specified and uses
   .Aq TAB
   as the field separator.
   In order to use a literal
   .Sq t
   as the field separator, use the
   .Fl F
   option with a value of
   .Sq [t] .
   .Pp
 A pattern-action statement has the form  A pattern-action statement has the form
 .Pp  .Pp
 .D1 Ar pattern Ic \&{ Ar action Ic \&}  .D1 Ar pattern Ic \&{ Ar action Ic \&}
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 a missing pattern always matches.  a missing pattern always matches.
 Pattern-action statements are separated by newlines or semicolons.  Pattern-action statements are separated by newlines or semicolons.
 .Pp  .Pp
   Newlines are permitted after a terminating statement or following a comma
   .Pq Sq ,\& ,
   an open brace
   .Pq Sq { ,
   a logical AND
   .Pq Sq && ,
   a logical OR
   .Pq Sq || ,
   after the
   .Sq do
   or
   .Sq else
   keywords,
   or after the closing parenthesis of an
   .Sq if ,
   .Sq for ,
   or
   .Sq while
   statement.
   Additionally, a backslash
   .Pq Sq \e
   can be used to escape a newline between tokens.
   .Pp
 An action is a sequence of statements.  An action is a sequence of statements.
 A statement can be one of the following:  A statement can be one of the following:
 .Bd -unfilled -offset indent  .Bd -unfilled -offset indent
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 are permitted; the constituents are concatenated,  are permitted; the constituents are concatenated,
 separated by the value of  separated by the value of
 .Va SUBSEP  .Va SUBSEP
 (see  .Pq see the section on variables below ) .
 .Sx VARIABLES  
 below).  
 .Pp  .Pp
 The  The
 .Ic print  .Ic print
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 statement formats its expression list according to the format  statement formats its expression list according to the format
 (see  (see
 .Xr printf 3 ) .  .Xr printf 3 ) .
   .Pp
   Patterns are arbitrary Boolean combinations
   (with
   .Ic "\&! || &&" )
   of regular expressions and
   relational expressions.
   Regular expressions are as in
   .Xr egrep 1 .
   Isolated regular expressions
   in a pattern apply to the entire line.
   Regular expressions may also occur in
   relational expressions, using the operators
   .Ic ~
   and
   .Ic !~ .
   .Pf / Ns Ar re Ns /
   is a constant regular expression;
   any string (constant or variable) may be used
   as a regular expression, except in the position of an isolated regular expression
   in a pattern.
   .Pp
   A pattern may consist of two patterns separated by a comma;
   in this case, the action is performed for all lines
   from an occurrence of the first pattern
   through an occurrence of the second.
   .Pp
   A relational expression is one of the following:
   .Bd -unfilled -offset indent
   .Ar expression matchop regular-expression
   .Ar expression relop expression
   .Ar expression Ic in Ar array-name
   .Ic \&( Ns Xo
   .Ar expr , expr , \&... Ns Ic \&) in
   .Ar \& array-name
   .Xc
   .Ed
   .Pp
   where a
   .Ar relop
   is any of the six relational operators in C, and a
   .Ar matchop
   is either
   .Ic ~
   (matches)
   or
   .Ic !~
   (does not match).
   A conditional is an arithmetic expression,
   a relational expression,
   or a Boolean combination
   of these.
   .Pp
   The special patterns
   .Ic BEGIN
   and
   .Ic END
   may be used to capture control before the first input line is read
   and after the last.
   .Ic BEGIN
   and
   .Ic END
   do not combine with other patterns.
   .Pp
   Variable names with special meanings:
   .Pp
   .Bl -tag -width "FILENAME" -compact
   .It Va ARGC
   Argument count, assignable.
   .It Va ARGV
   Argument array, assignable;
   non-null members are taken as filenames.
   .It Va CONVFMT
   Conversion format when converting numbers
   (default
   .Qq Li %.6g ) .
   .It Va ENVIRON
   Array of environment variables; subscripts are names.
   .It Va FILENAME
   The name of the current input file.
   .It Va FNR
   Ordinal number of the current record in the current file.
   .It Va FS
   Regular expression used to separate fields; also settable
   by option
   .Fl F Ar fs .
   .It Va NF
   Number of fields in the current record.
   .Va $NF
   can be used to obtain the value of the last field in the current record.
   .It Va NR
   Ordinal number of the current record.
   .It Va OFMT
   Output format for numbers (default
   .Qq Li %.6g ) .
   .It Va OFS
   Output field separator (default blank).
   .It Va ORS
   Output record separator (default newline).
   .It Va RLENGTH
   The length of the string matched by the
   .Fn match
   function.
   .It Va RS
   Input record separator (default newline).
   .It Va RSTART
   The starting position of the string matched by the
   .Fn match
   function.
   .It Va SUBSEP
   Separates multiple subscripts (default 034).
   .El
 .Sh FUNCTIONS  .Sh FUNCTIONS
 The awk language has a variety of built-in functions:  The awk language has a variety of built-in functions:
 arithmetic, string, input/output and general.  arithmetic, string, input/output and general.
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 Parameters are local to the function; all other variables are global.  Parameters are local to the function; all other variables are global.
 Thus local variables may be created by providing excess parameters in  Thus local variables may be created by providing excess parameters in
 the function definition.  the function definition.
 .Sh PATTERNS  
 Patterns are arbitrary Boolean combinations  
 (with  
 .Ic "\&! || &&" )  
 of regular expressions and  
 relational expressions.  
 Regular expressions are as in  
 .Xr egrep 1 .  
 Isolated regular expressions  
 in a pattern apply to the entire line.  
 Regular expressions may also occur in  
 relational expressions, using the operators  
 .Ic ~  
 and  
 .Ic !~ .  
 .Pf / Ns Ar re Ns /  
 is a constant regular expression;  
 any string (constant or variable) may be used  
 as a regular expression, except in the position of an isolated regular expression  
 in a pattern.  
 .Pp  
 A pattern may consist of two patterns separated by a comma;  
 in this case, the action is performed for all lines  
 from an occurrence of the first pattern  
 through an occurrence of the second.  
 .Pp  
 A relational expression is one of the following:  
 .Bd -unfilled -offset indent  
 .Ar expression matchop regular-expression  
 .Ar expression relop expression  
 .Ar expression Ic in Ar array-name  
 .Ic \&( Ns Xo  
 .Ar expr , expr , \&... Ns Ic \&) in  
 .Ar \& array-name  
 .Xc  
 .Ed  
 .Pp  
 where a  
 .Ar relop  
 is any of the six relational operators in C, and a  
 .Ar matchop  
 is either  
 .Ic ~  
 (matches)  
 or  
 .Ic !~  
 (does not match).  
 A conditional is an arithmetic expression,  
 a relational expression,  
 or a Boolean combination  
 of these.  
 .Pp  
 The special patterns  
 .Ic BEGIN  
 and  
 .Ic END  
 may be used to capture control before the first input line is read  
 and after the last.  
 .Ic BEGIN  
 and  
 .Ic END  
 do not combine with other patterns.  
 .Sh VARIABLES  
 Variable names with special meanings:  
 .Pp  
 .Bl -tag -width "FILENAME" -compact  
 .It Va ARGC  
 Argument count, assignable.  
 .It Va ARGV  
 Argument array, assignable;  
 non-null members are taken as filenames.  
 .It Va CONVFMT  
 Conversion format used when converting numbers  
 (default  
 .Qq Li %.6g ) .  
 .It Va ENVIRON  
 Array of environment variables; subscripts are names.  
 .It Va FILENAME  
 The name of the current input file.  
 .It Va FNR  
 Ordinal number of the current record in the current file.  
 .It Va FS  
 Regular expression used to separate fields; also settable  
 by option  
 .Fl F Ar fs .  
 .It Va NF  
 Number of fields in the current record.  
 .It Va NR  
 Ordinal number of the current record.  
 .It Va OFMT  
 Output format for numbers (default  
 .Qq Li %.6g ) .  
 .It Va OFS  
 Output field separator (default blank).  
 .It Va ORS  
 Output record separator (default newline).  
 .It Va RLENGTH  
 The length of the string matched by the  
 .Fn match  
 function.  
 .It Va RS  
 Input record separator (default newline).  
 .It Va RSTART  
 The starting position of the string matched by the  
 .Fn match  
 function.  
 .It Va SUBSEP  
 Separates multiple subscripts (default 034).  
 .El  
 .Sh EXAMPLES  .Sh EXAMPLES
 Print lines longer than 72 characters:  Print lines longer than 72 characters:
 .Pp  .Pp
Legend:
Removed from v.1.17  
changed lines
  Added in v.1.18