How to delete or remove duplicate lines in a file

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LEARN ABOUT DEBIAN

prunehistory

PRUNEHISTORY(8) 					      System Manager's Manual						   PRUNEHISTORY(8)

NAME

       prunehistory - remove file names from Usenet history file

SYNOPSIS

       prunehistory [ -f filename ] [ -p ] [ input ]

DESCRIPTION

       Prunehistory  modifies  the  history(5)	text file to ``remove'' a set of filenames from it.  The filenames are removed by overwriting them
       with spaces, so that the size and position of any following entries does not change.

       Prunehistory reads the named input file, or standard input if no file is given.	The input is taken as a set of	lines.	 Blank	lines  and
       lines  starting	with a number sign (``#'') are ignored.  All other lines are should consist of a Message-ID followed by zero or more file-
       names.

       The Messge-ID is used as the dbz(3) key to get an offset into the text file.  If no filenames are mentioned on the  input  line,  then  all
       filenames  in the text are ``removed.''	If any filenames are mentioned, they are converted into the history file notation.  If they appear
       in the line for the specified Message-ID then they are removed.

       Since innd(8) only appends to the text file, prunehistory does not need to have any interaction with it.

OPTIONS

       -p     Prunehistory will normally complain about lines that do not follow the correct format.  If the ``-p'' flag is used, then the program
	      will silently print any invalid lines on its standard output.  (Blank lines and comment lines are also passed through.)  This can be
	      useful when prunehistory is used as a filter for other programs such as reap.

       -f     The default name of the history file is /var/lib/news/history; to specify a different name, use the ``-f'' flag.

EXAMPLES

       It is a good idea to delete purged entries and rebuild the dbz database every so often by using a script like the following:

	      ctlinnd throttle "Rebuilding history database"
	      cd /var/lib/news
	      awk 'NF > 2 {
		   printf "%s	%s	%s", $1, $2, $3;
		   for (i = 4; i <= NF; i++)
			printf " %s", $i;
		   print "
";
	      }' <history >history.n
	      if makehistory -r -f history.n ; then
		  mv history.n history
		  mv history.n.pag history.pag
		  mv history.n.dir history.dir
	      else
		  echo 'Problem rebuilding history; old file not replaced'
	      fi
	      ctlinnd go "Rebuilding history database"

       Note that this keeps no record of expired articles.

HISTORY

       Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews.  This is revision 1.9, dated 1996/10/29.

SEE ALSO

       dbz(3), history(5), innd(8).

																   PRUNEHISTORY(8)

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