Perl's rename: GATES, Bill -> Bill Gates

Question

Suppose I have files named like GATES, Bill.jpg and I want to rename them all to Bill Gates.jpg. I can capture the two words

rename 's/^(.*?), (.*?)\./$2 $1\./g' *

To change a case there are some Perl's functions:

$lower = lc("aBcDe");  # $lower is assigned "abcde" 
$upper = uc("aBcDe");  # $upper is assigned "ABCDE"
$lower = lcfirst("HELLO");  # $lower is assigned "hELLO" 
$upper = ucfirst("hello");  # $upper is assigned "Hello"

I tried to make use of them:

rename 's/^(.*?), (.*?)\./$2 ucfirst($1)\./g' *

But it doesn't work.

Answer 1

You need to add the "e" (eval) flag to the end of the regular expression, otherwise the function won't be executed. This means that the entire second part of the s/// expression has to be a valid Perl expression (instead of a valid string):

rename 's/^(.*?), (.*?)\./"$2 " . ucfirst(lc($1)) . "."/ge' *

(also note the extra space inside the string with $2)

More information on this flag can be found in the perlre documentation.