Using sed with wildcards

[Jeff Gyurko]

Hi,

I've a need to substitute some string in a line where I do not what the string is currently, only what I need it to be. I've been trying, with no luck to use sed so I'm turning to the group. A sample line follows:

TXT=getsearch ("THISISIT", "This is always the same: ",3);

Now I have a need to replace THISISIT which I will not know with something else that I do know. The TXT= is unique so I could key off that to get the target line I want to modify. I've tried a number of things, but I'm either not qualifying any lines or I get something like TXT=getsearch ("THISISIT"TXT=getsearch ("THISISIT", "This is always the same: ",3);

Hope I've described it well enough.

[Pat Lieberg]

How about:

sed 's/"[^"]*"/"replacement string"/' filename

[curt larson_1]

how about trying something in awk

awk -F"\"" '
/TXT=/ {printf("%s\"%s",$1,"yourtext");
for ( i=3;iprint $NF;
}'

sed could be something like this

sed -e 's/^\(TXT=getsearch ("\)[:alnum:]*\(", "This is always.*$\)/\1yourtext\2/

[Jeff Gyurko]

Pat,

It worked to a point. It changed any occurance of that to THISISIT. Since there are other instances of it in the file they were all changed to THISISIT.

What I did do, taking your suggestion is add the qualifier PW1 to the sed like:

sed '/PW1=/s/"[^"]*"/"replacement string"/' filename.

It changed the one line with PW1.

Thanks a bunch.

[Jeff Gyurko]

Sorry Pat, the correct line was

sed '/TXT=/s/"[^"]*"/"replacement string"/' filename.

Not PW1. PW1 was still in my cut/paste buffer.

[TwoProc]

Jeff,

I've handled this same problem in the past by generating a sed command file on each occurence of the new "unknown" with a replacement command for sed.
I generate that file into /var/tmp/sed.$$
and then run my sed against that new command file with the "-f" option for sed.

Probably a little clunky, but it has allowed me to get the job done everytime, as it is easy to build rather complex multiple sed command sets into a file and use it a base to change many files using the one command file.

[Pat Lieberg]

oops, good catch. I overlooked that compeltely.

Glad I at least got you on the right track.

[James R. Ferguson]

HI Jeff:

How about:

perl -ne 's!(.+),(.+),(.+)!"newstring",$2,$3!;print' yourfile

...where "newstring" is the replacement for the THISISIT.

Regards!

...JRF...

[Hein van den Heuvel]

perl -pe 's/"$1"/"new text"/ if /^TXT.*\("(\w+)"/' old > new

$1 gets the (\w+) on a match.

The "" around $1 and new word in the substitute are belts and suspenders.... in case the the old text is 'TXT' or such.

The $1 can be remembered eg: $thisisit=$1
and used for further substitutes in different context in the file.

perl -pe '$thisisit = $1 if /^TXT.*\("(\w+)"/;
s/$thisisit/new text/ if defined ($thisisit)' old > new

Check out the perl -i option for 'in place' edits.

Hein.

[Jeff Gyurko]

James,

Thanks, but your solution changed every occurance and chopped off any text preceeding what I changed.

ie: every changed line started with ^"THISISIT

Trouble is, unlike sed, my breadth of knowledge in perl is not that much so I can make modifications to your suggestion.