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Full Discussion: Help on for loop in bash
Top Forums Shell Programming and Scripting Help on for loop in bash Post 302975828 by Don Cragun on Sunday 19th of June 2016 04:25:36 PM
Old 06-19-2016
There are several things that seem strange in your script, but some of what I'm seeing may just be a nomenclature problem. You have a variable named pattern and you have shown us the code segment:
Code:
test $# -eq 0 && read pattern
for pattern in "$pattern"
do
  result=
  for dir in $dirpath
  do
    for file in $dir/$pattern

which (even ignoring the missing do and three done commands) can't possibly be what you want. If $pattern expands to a list of files or a list of pathnames, the first time through the loop started with:
Code:
for pattern in "$pattern"

will set pattern to be the entire list and you will never go through that loop more than once.

And, if $pattern contains any filename pattern special characters (e.g., ?, *, [list], etc.), they will not be expanded inside double quotes.

When you enter patterns on the command line when you invoke your script are the patterns quoted (so the shell doesn't perform pattern matching before invoking your script)? When you read patterns from standard input, are they really patterns or are they just pathnames of files?
Last edited by Don Cragun; 06-19-2016 at 06:23 PM.. Reason: Fix misleading statement.
 

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LEARN ABOUT OPENSOLARIS

ppmtosixel

ppmtosixel(1)                                                 General Commands Manual                                                ppmtosixel(1)

NAME

       ppmtosixel - convert a portable pixmap into DEC sixel format

SYNOPSIS

       ppmtosixel [-raw] [-margin] [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as input.  Produces sixel commands (SIX) as output.  The output is formatted for color printing, e.g. for a DEC
       LJ250 color inkjet printer.

       If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled.  A printer control header and a color assignment table
       begin the SIX file.  Image data is written in a compressed format by default.  A printer control footer ends the image file.

OPTIONS

       -raw   If  specified,  each  pixel  will  be explicitly described in the image file.  If -raw is not specified, output will default to com-
              pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands.  A raw file is often an order  of  magni-
              tude larger than a compressed file and prints much slower.

       -margin
              If  -margin  is not specified, the image will be start at the left margin (of the window, paper, or whatever).  If -margin is speci-
              fied, a 1.5 inch left margin will offset the image.

PRINTING

       Generally, sixel files must reach the printer unfiltered.  Use the lpr -x option or cat filename > /dev/tty0?.

BUGS

       Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion.  If the original PPM maxval was
       greater  than  100,  rescaling  also reduces the image depth.  While the actual RGB values from the ppm file are more or less retained, the
       color palette of the LJ250 may not match the colors on your screen.  This seems to be a printer limitation.

SEE ALSO

       ppm(5)

AUTHOR

       Copyright (C) 1991 by Rick Vinci.

                                                                   26 April 1991                                                     ppmtosixel(1)
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