Question : searching sentence and replace it in bash script

Can it be possible to write shell script that will replace same sentence in many files under some directory to my desired sentence? I know that grep can be used to search specific syntax in files under any directory. But if i want to replace anyhting is there any ready command available on redhat linux systems?

Answer : searching sentence and replace it in bash script

Perl or sed are great for this. Depending on your type/version of sed, you can edit in place. Perl can also edit in place this way:

perl -pi.bak -we's/some string to search for/replace with this/;' your-file.txt

or for many files:

find /some/directory -name 'your-file-wildcard.*' | xargs perl -pi.bak -we's/some string to search for/replace with this/;'

Or sed (some versions):

sed -i.bak 's/some string to search for/replace with this/' your-file.txt

Note that the s/// takes a regular expression (like egrep) for the first argument.