How to verify if an arg is a valid file name in Shell?

Question

I need to verify if the args are valid file names, is this the right way to do it? It seems like I made some mistake inline 2, but I don't know where.

for i in ${@}; do                                   
if [ -f ${i}]; then                             
    echo ${i}
else continue
fi
done

Answer 1

First of all, you need a space before the closing square bracket. And you should quote your variables in case there's a space in a filename.

for i in "${@}"; do 
if [ -f "${i}" ]; then
    echo "${i}"
else continue
fi
done

The "else continue" is unnecessary, unless that's a placeholder for something else you plan to put in place of "continue".

Answer 2

Here is a terse solution, which works even if file names contain spaces:

for i
do
    test -f "$i" && echo "$i"
done

Note that the for statement assumes the command line arguments, there is no need to type more. The test command is a short way of if .. then .. fi

Answer 3

-f checks that ${i} is a regular file.