Man Pages

wrjpgcom(1) - phpMan wrjpgcom(1) - phpMan

Command: man perldoc info search(apropos)  


WRJPGCOM(1)                                                        WRJPGCOM(1)



NAME
       wrjpgcom - insert text comments into a JPEG file

SYNOPSIS
       wrjpgcom [ -replace ] [ -comment text ] [ -cfile name ] [ filename ]


DESCRIPTION
       wrjpgcom  reads  the  named  JPEG/JFIF  file,  or  the  standard input if no file is named, and generates a new
       JPEG/JFIF file on standard output.  A comment block is added to the file.

       The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file.   Although  the  standard  doesn't
       actually  define  what  COM blocks are for, they are widely used to hold user-supplied text strings.  This lets
       you add annotations, titles, index terms, etc to your JPEG files, and later retrieve them as text.  COM  blocks
       do  not  interfere with the image stored in the JPEG file.  The maximum size of a COM block is 64K, but you can
       have as many of them as you like in one JPEG file.

       wrjpgcom adds a COM block, containing text you provide, to a JPEG file.  Ordinarily, the  COM  block  is  added
       after any existing COM blocks; but you can delete the old COM blocks if you wish.

OPTIONS
       Switch names may be abbreviated, and are not case sensitive.

       -replace
              Delete any existing COM blocks from the file.

       -comment text
              Supply text for new COM block on command line.

       -cfile name
              Read text for new COM block from named file.

       If  you  have  only one line of comment text to add, you can provide it on the command line with -comment.  The
       comment text must be surrounded with quotes so that it is treated as a single argument.  Longer comments can be
       read from a text file.

       If  you  give  neither  -comment nor -cfile, then wrjpgcom will read the comment text from standard input.  (In
       this case an input image file name MUST be supplied, so that the source JPEG file comes from  somewhere  else.)
       You can enter multiple lines, up to 64KB worth.  Type an end-of-file indicator (usually control-D) to terminate
       the comment text entry.

       wrjpgcom will not add a COM block if the provided comment string is empty.  Therefore -replace -comment ""  can
       be used to delete all COM blocks from a file.

EXAMPLES
       Add a short comment to in.jpg, producing out.jpg:

              wrjpgcom -c "View of my back yard" in.jpg > out.jpg

       Attach a long comment previously stored in comment.txt:

              wrjpgcom in.jpg < comment.txt > out.jpg

       or equivalently

              wrjpgcom -cfile comment.txt < in.jpg > out.jpg

SEE ALSO
       cjpeg(1), djpeg(1), jpegtran(1), rdjpgcom(1)

AUTHOR
       Independent JPEG Group



                                 15 June 1995                      WRJPGCOM(1)