2.0;chpat (change_pattern), revision 2.0, 86/11/04
CHPAT (CHANGE_PATTERN) -- Replace pattern in text file.
usage:  CHPAT [-A|-X] [-L] [-O] [-OUT [pathname]] [pathname...]  [-P] [pat...]
                                        from_pattern [to_expr]


FORMAT

  CHPAT [options] [pathname ...] [-P] [pat ...]  from_pattern [to_expression]


  CHPAT  copies  every  line  from its input files to its output files, globally
  substituting the text replacement pattern "to_expression" for each  occurrence
  of  "from_pattern"  in those lines designated by the "pat" argument(s) and any
  options.

  Refer to the descriptions of the ED (EDIT),  FPAT  (FIND_PATTERN),  and  EDSTR
  (EDIT_STREAM) commands for related information.


ARGUMENTS

  pathname
  (optional)          Specify  name  of file to be searched.  Multiple pathnames
                     and wildcarding are permitted.

                     Default if omitted:  search standard input.

  from_pattern
  (required)         Specify target  text  string  (a  regular  expression)  for
                     substitution  or  deletion.    If  the  string includes the
                     characters % $ [ ] { } !  *  or  any  other  Shell  special
                     characters,  enclose  it  in  quotes to avoid unpredictable
                     results. If the 'pathname'  argument  is  present,  precede
                     this argument (or the 'pat' argument, if present) with "-P"
                     to separate the pathname(s) from the regular expressions on
                     the command line.

  to_expression
  (optional)           Specify   replacement  string.    If  no  replacement  is
                     specified, the 'from_pattern' string will  be  deleted.  If
                     regular   expressions  defining  a  range  of  text  ('pat'
                     argument) are  present,  you  must  use  a  literally  null
                     'to_expression' ("") to delete 'from_pattern'.

  pat
  (optional)          Specify  range  of  text  for which the substitution is to
                     apply, in  the  form  of  a  regular  expression.  Multiple
                     expressions  separated  by  blanks  are  permitted.  Unless
                     modified by options, any line of text matching any  pattern
                     is  replaced  and all lines, changed or not, are written to
                     output.  If the 'pathname'  argument  is  present,  precede
                     this  argument  with  "-P" to separate the pathname(s) from
                     the regular expressions on the command line.

                     Default if omitted:  use 'from_pattern' to select matching
                                          lines.


OPTIONS

  -A                  Select  only  lines  that  match  all   of   the   leading
                     expressions, in any order.

  -X                   Select   only  lines  that  match  none  of  the  leading
                     expressions.

  -O                 Write only the selected  lines  to  standard  output.    By
                     default, CHPAT writes all lines to output.

  -L                  List  name(s)  of  input  file(s) on output file(s) as the
                     input file(s) are searched.

  -OUT pathname
                     Specify  name of output file.  Pathname may be derived from
                     the input file name.  If this option is omitted, output  is
                     written to standard output.


EXAMPLES

  1. $ chpat foo bar

     Changes all occurrences of 'foo' in standard input to  'bar'
     and writes the results to standard output.

  2. $ chpat '%This' "  *" ' '

     In  lines  starting  with  'This',  it changes all occurrences
     of multiple spaces to a single space.

  3. $ chpat '%This' '%That' "  *" ' '

     Like 2., but works  on  lines  starting  with  either  'This' or
     'That'.

  4. $ chpat -a '%when' 'only$' ';' ':'

     In  lines  that start with 'when' and end with 'only', change
     all semicolons to colons.

  5. $ chpat -x not none some all

     In lines that do not contain either 'not' or 'none',  change
     all instances of 'some' to 'all'.

  6. $ chpat erase

     Delete (replace with nothing) all occurences of 'erase'.
     Exactly the same effect can be obtained with:

     $ chpat erase ''

  7. $ chpat -o other_opts pat... fr_pat to_pat

       Is exactly the same as

     $ fpat pat... | chpat other_opts fr_pat to_pat

  8. $ chpat ?*.pas -out =.new -p "if x = y" "if (x = y)"

       Change  all  occurrences  of  the  string   "if x = y"
       to "if (x = y)"  in all Pascal source files (files  ending with
       '.pas') and put the output for 'X.pas' in 'X.pas.new'.


RELATED TOPICS

  More information is available.  Type:

  - HELP PATTERNS
   for details about regular expression syntax and usage.