Replace and add leading zeros when renaming files

Question

Please be patient, this post will be somewhat long ...

I have a bunch of files, some with a simple and clean name (for example, 1E01.txt), and some with a lot of extra features:

Sample2_Name_E01_-co_032.txt Sample2_Name_E02_-co_035.txt ... Sample12_Name_E01_-co_061.txt 

etc. The number after the “Sample” and the letter + the number after the “Name” are important here - the rest is one-time. If I get rid of the important parts, the file name comes down to the same pattern as the "clean" file names (2E01.txt, 2E02.txt, ..., 12E01.txt). I managed to rename the files with the following expression (I invented it myself, I don’t know if it is very elegant, but it works fine):

 rename -v 's/Sample([0-9]+)_Name_([AZ][0-9]+).*/$1$2\.txt/' *.txt 

Now the second part adds a leading zero for single-digit file names, for example, 1E01.txt turns into 01E01.txt. I managed to do this (found and changed it to another StackExchange post):

 rename -v 'unless (/^[0-9]{2}.*\.txt/) {s/^([0-9]{1}.*\.txt)$/0$1/;s/0*([0-9]{2}\..*)/$1/}' *.txt 

So, I finally got to my question: is there a way to combine both expressions in only one rename command? I know I can make a bash script to automate the process, but I want to find a one-pass renaming solution.

thanks

Answer 1

You can try this command to rename 1-file.txt to 0001-file.txt

 # fill zeros $ rename 's/\d+/sprintf("%04d",$&)/e' *.txt 

You can change the team a bit to suit your needs.

Answer 2

Well, if this is your regular expression "parsing", you limit the files that the script can act on those that match this pattern. So, sprintf using the same literals is not a more specialized case, and you could just do this:

 s{Sample(\d+)_Name_(\p{IsUpper})(\d+)} {sprintf "Sample%02d_Name_%s%03d", $1, $2, $3}e ; 

Here you again use the same well-known functions and simply format the accompanying numbers.

• /e switch for "eval" and evaluates the replacement as Perl for each match.
• I renamed some of your expressions to more standard character character characters: [AZ] becomes the property class \p{IsUpper} , [0-9] becomes the numeric code \d (it is also possible \p{IsDigit} ).