############################################################################
#
#	File:     trim.icn
#
#	Subject:  Program to trim lines in a file
#
#	Author:   Ralph E. Griswold
#
#	Date:     December 26, 1998
#
############################################################################
#
#   This file is in the public domain.
#
############################################################################
#  
#     This program copies lines from standard input to standard out-
#  put, truncating the lines at n characters and removing any trail-
#  ing blanks and tabs. The default value for n is 80.  For example,
#  
#          trim 70 <grade.txt >grade.fix
#  
#  copies grade.txt to grade.fix, with lines longer than 70 charac-
#  ters truncated to 70 characters and the trailing blanks removed
#  from all lines.
#  
#     The -f option causes all lines to be n characters long by
#  adding blanks to short lines; otherwise, short lines are left as
#  is.
#
############################################################################
#
#  Links: options
#
############################################################################

link options

procedure main(args)
   local n, pad, line, opts

   opts := options(args,"f")
   if \opts["f"] then pad := 1 else pad := 0
   n := (0 <= integer(args[1])) | 80

   while line := read() do {
      line := line[1+:n]
      line := trim(line, ' \t')
      if pad = 1 then line := left(line,n)
      write(line)
      }
end