ho w to replace a occurence of string by other string

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

Replies are listed 'Best First'.
Re: ho w to replace a occurence of string by other string by borisz (Canon) on Jan 18, 2005 at 13:22 UTC
untested: `perl -pe 's:(\w+\.data)\b:testname/$1:g' <input >output` [download] Boris	[reply] [d/l]
Re: how to replace ocurence of string with other string by Zaxo (Archbishop) on Jan 18, 2005 at 13:46 UTC
`perl -pi.bak -e'BEGIN{$testname="whatever"} s!([^/]+\.data)\b!$testname/$1!g' output.txt` That will make the substitutions into output.txt which is backed up in a file called output.txt.bak. [Update: edited for thinko, VSarkiss++] After Compline, Zaxo	[reply] [d/l]
Re: ho w to replace a occurence of string by other string by holli (Abbot) on Jan 18, 2005 at 14:56 UTC
this assumes your filenames consist only of a-z, A-Z and _ (which is the meaning of \w) and numbers 0-9 (which is the meaning of \d). oneliner: replaces all orrcurences in "infile" and leaves "infile.bak" with the original contents. `perl -npi.bak -e "s:([\w\d]+\.data):testname/$1:g" infile` [download] or as a script: `use strict; $testname="replacement"; open IN, "infile" or die $!; open OUT, ">outfile" or die $!; while ( <IN> ) { s:([\w\d]+\.data):$testname/$1:g print OUT $_; } close IN; close OUT;` [download] Update: As borisz /msg-ed me, \w includes \d. thus `[\w\d]`is equivavelent to `[\w]`. holli, regexed monk	[reply] [d/l] [select]
how to modify the text in file by sachin_chat (Initiate) on Jan 19, 2005 at 06:37 UTC
i am using a file say file1.txt . in that file i am refering to files like xxx1.data etc. in all the occurences i want to append this string as $testname/xxx1.data( preceed the xxx1.data with $testname. here $testname is a variable name which is having some value and has been set earlier and i m using its value by calling the scalar). now what i had tried actually replaces the xxx1.data , i do not want to delete the string only add new text before it. Thanks sachin	[reply]
Re: how to modify the text in file by Thilosophy (Curate) on Jan 19, 2005 at 07:07 UTC
now what i had tried actually replaces the xxx1.data , i do not want to delete the string only add new text before it. What have you tried? Show us some code... If you tried `s[\w\w\w1\.data][$testname/]g` [download] you might consider `s[(\w\w\w1\.data)][$testname/$1]g` [download] instead. The `$1` stands for the text enclosed in the first set of round brackets in the pattern.	[reply] [d/l] [select]
Re^2: how to modify the text in file by sachin_chat (Initiate) on Jan 19, 2005 at 07:19 UTC
i was using something like perl -npi.bak -e "s:(\w\d+\.data):testname/$1:g" file1.txt . it actually repleces the text and do not do what i wanted	[reply]
Re^3: how to modify the text in file by dse (Novice) on Jan 19, 2005 at 07:31 UTC
Re^3: how to modify the text in file by Thilosophy (Curate) on Jan 19, 2005 at 07:30 UTC