Replace all dots in filenames except the extension on Linux
for f in .; do pre="${f%.}"; suf="${f##.}"; mv -i -f -- "$f" "${pre//./_}.${suf}"; done
Cli
Count number of directories in the current directory using Linux cli
ls -1 | wc -l
Count number of files in a directory using Linux cli
ls -l . | egrep -c '^-'