how to replace certain patterns in a file thru unix!!

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1

Hi Friends,
well what i want to do is that suppose i have a file say like
....
ronaldduckdancecoolman
donaldmuckdancepooltactics
fonaldguckdancetoolbutcomps
....
okok i agree this is a ridiculous data for a file.
:slight_smile:
now i want that the characters in each line fromposition 16 to say 19 gets replaced by a particular string , in this case the charcters are cool pool and tool , so say i want is the follwoing output:

....
ronaldduckdanceYYYYman
donaldmuckdanceYYYYtactics
fonaldguckdanceYYYYbutcomps
....

or maybe it is possible that the case is that i want to replcae cool,tool and pool by word whose length is greate than the ones which are present say like

....
ronaldduckdanceYYYYYYYYman
donaldmuckdanceYYYYYYYYtactics
fonaldguckdanceYYYYYYYYbutcomps
....

and also suppose i want say that a particular word occurence in every line is replaced by some other word say like i have input file containing

....
ronaldduckdanceYYYYman
donaldmuckdanceYYYYtactics
fonaldguckdanceYYYYbutcomps
....

and i want the file to be manipulated as
....
ronaldduckdanceXXXXman
donaldmuckdanceXXXXtactics
fonaldguckdanceXXXXbutcomps
....

or say different lengths replacement like
....
ronaldduckdanceXXXXXXXXman
donaldmuckdanceXXXXXXXXtactics
fonaldguckdanceXXXXXXXXbutcomps
....

the bottomline being that there r 2 cases one being replacement being on base of position and the other being replaxcement on basis of certain pattern.

HOW do i do this????
PLzzz help

Regards
Manish

2

Sounds like you need "sed".
Check out...
http://wwwinfo.cern.ch/dis/texi2html/gnu/sed-3.02/sed_toc.html

3

aye sed does soudn liek the way you want to go.

sed 's/.ool/&ltreplacement string&gt/'

4

Hi,
Thanks a lot pals , one of the problems is solved but still one exists.
i am unable to replace based on positions,
could u shed some light on that part plzzzz.
Regards
Manish

5

you will want to look into sed. we gave you the key to open the door. you just have to turn the knob.

you will want to look into regular exprestions also.

6

Hi optimus,
i turned the knob!
looked in regular expresions too, but all i cud find is pattern replacement but noting on positional replacement!
Help if u can plzzz.
Regards
Manish

7

A few patterns to experiment with:

Some hints:

. is any character
......  is any 6 characters
.\{6\}  also any 6 characters
\(.\{6\}\) any 6 characters saved as subexpression
^\(.\{6\}\) first 6 characters saved as subexpression