Unix Tip: ENHANCED #1576 FILE REVERSAL

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UNIX HOT TIP

Unix Tip 3002 - April 26, 2010

http://www.ugu.com/sui/ugu/show?tip.today

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ENHANCED #1576 FILE REVERSAL

This is an enhancement to UNIX Tip #1576 - April 25, 2001.

The original tip is kind a cool, so I decided to enhance it.

I hope it's okay with the main author.

#!/bin/ksh
lns=`wc -l $1 | nawk '{ print $1 }`
{
cat $1 | awk '{ line[NR] = $0; }
{ for (i = NR; i > 0; --i) print line[i] }'
} >> $$.temp
tail -"$lns" $$.temp
rm $$.temp

This tip generously supported by: jena_m@hotmail.com

---------------------------------------

FILE REVERSAL

For those that don't have
the tac command, to reverse
a file in UNIX, you could use:

cat <file-name> | awk '{ line[NR] = $0;} END
{for(i=NR;i>1;i--) print line[i] }'

This tip generously supported by: chandramohan_k@infy.com

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