regex change should be applied in iputfile

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

hi all

perl -i -pe 's/\.mbh_succ_roam_i_vlr_e_plmn/\.new_mbh_succ_roam_i_vlr_
+e_plmn/g' <input_file>
[download]

file content,
__DATA__
.mbh_succ_roam_i_vlr_e_plmn   next
.mbh_succ_roam_i_vlr_e_plmn1  first
.mbh_succ_roam_i_vlr_e_plmn2  verify
[download]

when I run the perl oneliner with the input file all 3 lines are getting changed. what is the change should I need to make to change only first line. In other words how can I change the code to affect only if the word matches neglecting the rest of lines.

Comment on regex change should be applied in iputfile Select or Download Code

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Re: regex change should be applied in iputfile by GrandFather (Saint) on Jun 01, 2007 at 04:40 UTC
Add a word break anchor (\b) at the end of the word: `s/\.mbh_succ_roam_i_vlr_e_plmn\b/.../g` [download] DWIM is Perl's answer to Gödel	[reply] [d/l]
Re: regex change should be applied in iputfile by McDarren (Abbot) on Jun 01, 2007 at 04:47 UTC
All 3 lines are being changed, because all three lines are matching. So you need to change your pattern so that only the one you want will match. The thing that is different about the first is that it has no trailing digit. So the simplest way is probably to just add a `\s` to the end of your matching string. So you would have this: `perl -i -pe 's/\.mbh_succ_roam_i_vlr_e_plmn\s/\.new_mbh_succ_roam_i_vl +r_e_plmn/g' <input_file>` [download] Personally, I'd do it slightly differently. Perhaps like this: `perl -i -pe 's/\.mbh([_a-z]+)\s/\.new$1/g' < input_file` [download] cheers, Darren :)	[reply] [d/l] [select]
Re: regex change should be applied in iputfile by blazar (Canon) on Jun 01, 2007 at 15:22 UTC
when I run the perl oneliner with the input file all 3 lines are getting changed. what is the change should I need to make to change only first line. In other words how can I change the code to affect only if the word matches neglecting the rest of lines. Others told you what you were missing: a `\b`. Here, I'll give you some other WTDI (while saving some keystrokes and the risk to type something the wrong way): `perl -pe "s/\.(mbh_succ_roam_i_vlr_e_plmn\b)/.new_$1/g" input.txt perl -pe "s/\.(?=mbh_succ_roam_i_vlr_e_plmn\b)/.new_/g" input.txt` [download]	[reply] [d/l] [select]