Rename multiple files via shell script

Question

I want to rename the following files 0 , 0.001 ,0.002 , 0.003 ... , 0.035

into 0 , 1 , 2 , 3 ... , 35

How can I do it?

Answer 1

bash solution (provided extglob shell option is enabled - see pattern matching manual)

for i in 0.* ; do mv "$i" "${i##0.*(0)}" ; done

• ${i## delete longest match from beginning of i variable
• 0. matches the character sequence 0.
• *(0) means zero or more occurrences of 0

or this solution suggested by @Costas, which doesn't need the extglob option

for i in 0.* ; do mv "$i" "${i#${i%%[!0.]*}}" ; done

• ${i%% delete longest match from end of i variable
• * any character, zero or more times
• [!0.] characters other than 0.
• so, ${i%%[!0.]*} effectively deletes from first non 0 or . character till end. For ex: 35 gets deleted for 0.035, 1 for 0.001, str0.00456a for 0str0.00456a and entire string for str0.00456a
• the remaining characters (ex: 0.0 for 0.035 and 0.00 for 0.001 gets passed to ${i# which then deletes these characters from beginning of variable, resulting in 35 for 0.035 and 1 for 0.001

Further reading: Parameter Expansion

Answer 2

With rename (prename):

rename -n 's/^[^.]+\.0*([1-9]+)$/$1/' 0*

-n will do the dry-run, if you are satisfied with the changes to be made, do:

rename 's/^[^.]+\.0*([1-9]+)$/$1/' 0*

Example:

% rename -n 's/^[^.]+\.0*([1-9]+)$/$1/' 0*
0.001 renamed as 1
0.002 renamed as 2
0.003 renamed as 3
0.035 renamed as 35