CODEWITHSUNDEEP
perlfileunixreplacesed
Krishna Chikkala
Krishna Chikkala

Reputation: 91

replace a string from first line on multiple files

I got 10,000 text files which I have to make changes.

First line on every file contains a url.

By mistake for few files url missking 'com'

eg:
1) http://www.supersonic./psychology 
2) http://www.supersonic./social
3) http://www.supersonic.com/science

my task is to check and add 'com' if it is missing 

eg:
    1) http://www.supersonic.com/psychology 
    2) http://www.supersonic.com/social
    3) http://www.supersonic.com/science

all urls are of same domain(supersonic.com)

can you suggest me any fast and easy approach ?

Tried this : replacing supersonic./ with supersonic.com

sed -e '1s/supersonic.//supersonic.com/' *

no change in the output.

Upvotes: 0

Views: 804

Answers (2)

shellter
shellter

Reputation: 37288

You are very close with your code, but you need to account for the trailing / char after the . char.

Assuming you are using a modern sed with the -i (inplace-edit) option you can do

sed -i '1s@supersonic\./@supersonic.com/@' *

Note that rather than have to escape / inside of the s/srchpat\/withSlash/replaceStr/', you can use another char after the the s command as the delimiter, here I use s@...@...@. If your search pattern had a @ char, then you would have to use a different char.

Some older versions of sed need to you to escape the alternate delimiter at the first use, so

     sed 's\@srchStr@ReplStr@' file

for those cases.

If you're using a sed that doesn't support the -i options, then you'll need to loop on your file, and manage the tmp files, i.e.

 for f in *.html ; do
    sed '1s@supersonic\./@supersonic.com/@' "$f" > /tmp/"$f".fix \
    && /bin/mv /tmp/"$f".fix "$f"
 done

Warning

But as you're talking about 10,000+files, you'll want to do some testing before using either of these solutions. Copy a good random set of those files to /tmp/mySedTest/ dir and run one of these solutions there to make sure there are no surprises.

And you're likely to blow out the cmd-line MAX_SIZE with 10,000+ files, so read about find and xargs. There are many posts here about [sed] find xargs. Check them out if needed.

IHTH

Upvotes: 1

choroba
choroba

Reputation: 241918

  1. Use -i to change the files instead of just outputting the changed lines.

  2. Use a different delimiter than / if you want to use / in the regex (or use \/ in the regex).

  3. Use \. to match a dot literally, . matches anything.

    sed -i~ -e '1s=supersonic\./=supersonic.com/=' *

Some versions of sed don't support -i.

Upvotes: 2

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