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Full Discussion: combining perl regex'es into a single command
Top Forums Shell Programming and Scripting combining perl regex'es into a single command Post 302355597 by hcclnoodles on Wednesday 23rd of September 2009 09:50:55 AM
Old 09-23-2009
thank you pludi , im not sure i fully understand whats going on here but at a guess

Code:
$filesystem=~s#.+/(\w+?/\w+?)/?$#$1#;

a) We are using hashes as delimiters

b) The .+/ would match more than one character except for a newline up to the first forward slash, i guess I am ok to put ^ in front of the dot to ensure we are matching against the beginning of the string ??

c) The bracket section is matching 1 or more word then slash then 1 or more words again ??? (to be honest im a little confused why this is in brackets)

d) The /?$ bit is matching against 0 or 1 instances of "/" at the end of the string .... I have changed this to /*$ just in case somebody puts more than one slash at the end

e) I really have no idea why there is a $1 in the 'substitute to' section of the statement ....what does this signify ?, I assume it must be a variable as opposed to a regex because wouldnt it replace the whole line with a number 1 ?? im very confused over how that bit works



Additionally, i tried adding a newline after the original string (\n) and your statement didnt remove it. Is it the case that I would still have to run a chomp on it afterwards or can that be integrated too ?

---------- Post updated at 02:50 PM ---------- Previous update was at 12:22 PM ----------

aha, figured it out ... the $1 is a back-reference and effectively whatever is matched between the parentheses in the "substitute-from" section, will populate the "substitute-to" section.. took me a while to get my head around but now i understand


thanks pludi
 

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set_color

set_color(1)							       fish							      set_color(1)

NAME

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set_color - set the terminal color
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