Remove whitespaces from filenames in Linux

The following would work in case it was really a space.

$ rename "s/ //g" *

Try

$ rename "s/\s+//g" *

\s is a whitespace character, belonging to the set of [ \t\r\n].

You could do something like this:

IFS="\n"
for file in *.jpg;
do
    mv "$file" "${file//[[:space:]]}"
done