Shell Programming and Scripting

Hi all

i need some help in writing a small script that searches a string and then replaces it by a new string
for searching the best result i get is from find comand combined with xargs
e.g.
find . -name "*.*" |xargs grep -l "search string"
this command I use in root directory and this gets me all the file in that directory and sub directories that has that string
I want to replace that string with new string in the files that gets as output from the find command.

Code:

find . -name '*' -type f -exec grep -l 'pattern' {} \; | \
while read file
do
      sed 's/pattern/newpattern/g' $file > ./tmp.tmp
      mv ./tmp.tmp $file
done

is one way to do it.

This is a perfectly horrible idea. Unless you like rebuilding your system.

A global search can change system files and protections on those files, for example. In other words, it is likely that your system will not reboot correctly, depending on what string/file you are changing. Limit the search with -user <some username not root or bin>.

Thanks for help
for your doubt regarding system files getting changed....
i will be running it from a specified location and "." specifies present location and sub directories inside the directory.
Also i will be modifying it to look for .pl files

I tested the script also and it works!!!!

find . -name "*.*" |xargs sed -i 's/string/string-to-replace/'

Would recommend not relying on the . and your current location. Imagine the script finding its way to /etc/passwd with your instruction to change 'root' to 'branch' (I am just making this up as I type) -- think you will be able to login again? If you 'know' the location, account for it so as to prevent future troubles.

Probably should not be searching for *.* -- perhaps *.txt or similar to minimize chance of changing something.

And this comes from someone who "thought he programmed for everything" until something went awry and I changed the permissions on every file in my system (old job) with a run-away find command. We weren't live yet (still loading files), so I could restore a backup and correct my errant script.

Lastly, using the find in this manner could mean exceptionally long execution times.