What does -f mean in bash
Google is useless in this case because searching for flags is useless
Fortunately, the Bash Reference Manual is available online, at http://www.gnu.org/software/bash/manual/bashref.html. It's the first hit when you Google for "Bash manual". ยง6.4 "Bash Conditional Expressions" says:
-f fileTrue if file exists and is a regular file.
-f - file is a regular file (not a directory or device file)
Check this out for all file test operators:http://tldp.org/LDP/abs/html/fto.html