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How to retain the header information of a file

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Old 12-04-2007
How to retain the header information of a file


I am using Bash shell to create some data and these data would be piped out to a file, let say output.txt.

This output.txt I would like to add some extra header information such as comments, descriptions and general information on the text.

I would like to know how could I maintain this type of information. I did try out using append to a file. In other word,I created a file with initial description and comments on it. Then, these data I would append (using << output.txt).

However, one limitation of this is that the data would be keep adding on top of the file each time repeated command are executed. Anyone have idea to solve this?

Besides, another problem is by having this header, I would like to further extract the data from the output.txt without the description and comments. I tried using head and tail but it doesnt work automatically. In other words, let say description and comment I have as first 5 lines of the output.txt. Currently I extract out these data using cat output.txt|..<all the operation>. But I could not help but extracting the first 5 lines as well.

Please advise. Appreciate alot.



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VORBISCOMMENT(1)						   Vorbis Tools 						  VORBISCOMMENT(1)

vorbiscomment - edits Ogg Vorbis comments SYNOPSIS
vorbiscomment [-l] file.ogg vorbiscomment -a [ -t "tag=value" ] in.ogg out.ogg vorbiscomment -w in.ogg out.ogg DESCRIPTION
vorbiscomment reads, modifies, and appends Ogg Vorbis audio file metadata tags. OPTIONS
-a Append comments. -c commentfile Take comments from a file. The file is the same format as is output by the the -l option: one element per line in 'tag=value' for- mat. -h Show command help. -l List the comments in the ogg vorbis file. -q Quiet mode. No messages are displayed. -t 'tag=value' Specify a new tag on the command line. Each tag is given as a single string. The part before the '=' is treated as the tag name and the part after as the value. -w Replace comments with the new set given either on the command line with -t or from a file with -c. EXAMPLES
To just see what comment tags are in a file: vorbiscomment -l file.ogg To edit those comments: vorbiscomment -l file.ogg > file.txt [edit the comments in file.txt to your statisfaction] vorbiscomment -w -c file.txt file.ogg newfile.ogg To simply add a comment: vorbiscomment -a -t 'ARTIST=No One You Know' file.ogg newfile.ogg SEE ALSO
See for documentation on the Ogg Vorbis tag format, including a suggested list of canonical tag names. AUTHORS
Program Authors: Michael Smith <> Ralph Giles <> Manpage Author: Christopher L Cheney <> Foundation December 24, 2001 VORBISCOMMENT(1)

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