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Shell Programming and Scripting

reversing order of lines in a file

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# 8  
Old 03-02-2007
This might be a bit faster:
nl -ba inputfile | sort -nr | cut -f2-
# 9  
Old 03-02-2007
Quote:
Originally Posted by alfredo123
Try this...

Code:
cat -n <filename>| sort -r | cut -f2-20 > reversedfile

Experts please comment if anything wrong with this.... Smilie
I think you should use "awk" instead of cut.

cat -n <filename> | sort -r | awk '{print $2}' > reversedfile
# 10  
Old 03-03-2007
tail -r <filename>

would reverse entire file.
# 11  
Old 03-03-2007
Quote:
Originally Posted by gopidesaboyina
tail -r <filename>

would reverse entire file.
The -r option to tail is not standard; it is available on *BSD, but not GNU.

Code:
$ tail -r .bashrc
tail: invalid option -- r
Try `tail --help' for more information

# 12  
Old 03-05-2007
reverse.pl
Code:
#!/usr/bin/perl
print reverse <>;

Code:
reverse.pl filename

# 13  
Old 01-07-2009
use command tac.

tac file1 > file1.tmp
mv file1.tmp file1 Smilie
# 14  
Old 01-07-2009
A way to reverse the file and preserve the order. Number the lines, sort, remove the numbers.

cat -n myfile| sort -n -r -k 1 |cut -f2-
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