Shortest way to replace a string

nikfr has asked for the wisdom of the Perl Monks concerning the following question:

Hi,
i have a file containing strings like this:

30.00.02.53 some text here
54.00.70.13 some text here

30.00.02.36 some text here
54.00.70.13 some text here
70.00.00.23 some text here

30.00.11.05 some text here
30.00.00.00 some text here
30.00.00.13 some text here
54.00.70.13 some text here

and want to replace all what begins with 30.00 by 30.00.00.00
e.g. replace 30.00.02.53 by 30.00.00.00
What is the simplest (shortest) way to do this?

Thank you for your time!

Comment on Shortest way to replace a string

Replies are listed 'Best First'.
Re: Shortest way to replace a string by BrowserUk (Patriarch) on Sep 11, 2013 at 23:02 UTC
`perl -pE"s[30\.00\.\d\d\.\d\d][30.00.00.00]g;" infile > outfile` [download] With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l]
Re^2: Shortest way to replace a string by choroba (Cardinal) on Sep 11, 2013 at 23:08 UTC
Or `s/(?<=30\.00\.)[0-9][0-9]\.[0-9][0-9]/00.00/g` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re^3: Shortest way to replace a string by BrowserUk (Patriarch) on Sep 11, 2013 at 23:15 UTC
The spec was "shortest" and that's 10 keystrokes longer; and certainly no more efficient :) With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]
Re^4: Shortest way to replace a string by hdb (Monsignor) on Sep 12, 2013 at 05:34 UTC
Re^5: Shortest way to replace a string by hippo (Archbishop) on Sep 12, 2013 at 14:11 UTC
Re^4: Shortest way to replace a string by choroba (Cardinal) on Sep 11, 2013 at 23:24 UTC
Re^5: Shortest way to replace a string by BrowserUk (Patriarch) on Sep 11, 2013 at 23:32 UTC
Re: Shortest way to replace a string by mcshell (Novice) on Sep 12, 2013 at 02:29 UTC
`s/^(\d+)(\.00)[^\s]+/$1$2$2$2/g;`	[reply] [d/l]