Truncate File

trunc_programs.cfg defines a simple Perl script to truncate files, for example logs and other data files.  Many Pikt scripts invoke trunc.pl.

///////////////////////////////////////////////////////////////////////////////
//
// trunc_programs.cfg
//
///////////////////////////////////////////////////////////////////////////////

trunc.pl        // truncate a file

        #!=perl
        
        # trunc.pl -- truncate a file
        
        die "Usage:  trunc.pl <#lines> <file>\n" unless $#ARGV == 1 ;
        
        $LINES = $ARGV[0] ;
        $FILE = $ARGV[1] ;
        
        $BAK = "$FILE.bak.gz" ;
        $TMP = "$FILE.tmp" ;
        
        die "no $FILE file!\n" if (! -e $FILE) ;
        
        ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,
         $mtime,$ctime,$blksize,$blocks) = stat($FILE) ;
        
        unlink($BAK) ;
        system("=gzip -c $FILE > $BAK") ;
        chown($uid, $gid, $BAK) ;
        chmod($mode, $BAK) ;
        
        system("=tail -$LINES $FILE > $TMP") ;
        chown($uid, $gid, $TMP) ;
        chmod($mode, $TMP) ;
        rename($TMP, $FILE) ;

//////////////////////////////////////////////////////////////////////////////

On the piktmaster system, we would install the trunc.pl script to each PIKT slave system with the command:

# piktc -iv +P trunc.pl +H all        [or: ... -H down]

For more examples, see Samples.