replace a text pattern with the reverse of another text pattern

lothario · 07-25-2008, 02:35 AM

To replace all the occurrences of OLD_text_PATTERN with NEW_TEXT_PATTERN in a specific file, I do:

Code:

replace -s   'OLD_text_PATTERN'   'NEW_TEXT_PATTERN'   --   /tmp/the_specific_file

Now, I also need replace all the occurrences of 2nd_text_PATTERN with reverse(NEW_TEXT_PATTERN) in the same file.
In other words, replace all the occurrences of 2nd_text_PATTERN with NRETTAP_TXET_WEN

How can I do this?

chakka.lokesh · 07-25-2008, 02:49 AM

Quote:

Originally Posted by lothario

replace all the occurrences of 2nd_text_PATTERN with NRETTAP_TXET_WEN
How can I do this?

does the following help ful to you??

Quote:

sed 's/pattern_one/new_pattern_one/;s/pattern_two/new_pattern_two/' inputfile > outputfile

colucix · 07-25-2008, 03:21 AM

Code:

man rev

is what you need.

pixellany · 07-25-2008, 07:14 AM

Quote:

Originally Posted by colucix

Code:

man rev

is what you need.

Wow, the world's shortest man page....

rev seems to reverse the order of whole lines.

lothario;
I assume that you need some kind of general solution in which you replace some text with the reverse of another pattern. (Otherwise, you would just enter the specific pattern you want.)

Somewhere there must be a command for reversing a word, but I can't find it....

Please tell us more about what you are trying to accomplish. There might be some other solution.

colucix · 07-25-2008, 07:39 AM

Quote:

Originally Posted by pixellany

Wow, the world's shortest man page....

Yeah, it is one of the shortest I have ever seen!

Quote:

Originally Posted by pixellany

Somewhere there must be a command for reversing a word, but I can't find it....

The rev command do this as well:

Code:

$ echo NEW_TEXT_PATTERN | rev
NRETTAP_TXET_WEN

See man rev for details...

lothario · 07-25-2008, 02:43 PM

Thanks for all the tips.
I got it working yesterday and was busy using it.
Here it is ...

Code:

replace -s   'OLD_text_PATTERN'     `echo $any_TEXT_to_be_reversed | rev`   --   /tmp/target_File.txt