Question

How can I write a shell script file_readable which:

• accepts some number of names as arguments,

• checks each name to see if it is a regular file and readable, and

• outputs a count of the number of such files.

For example:

$ sh file_readable /etc/fstab /etc/ssh/ssh_host_rsa_key /etc/does-not-exist
1

Of these, only /etc/fstab is likely to both exist and be readable.

So far I have put this together but it does not work correctly – can anybody help me please ?:

#!/bin/sh

for filename in "$@"

do
        if test -f "$filename"
        then  echo | wc -l
        else echo $?
fi
done

Answer 1

then echo | wc -l

If file exists and is a regular you print number of lines in empty string plus “\n”, which is equal 1 always. Sound not quite usable, isn’t it?

All you need is incrementing some counter and printing it in the end.

#!/bin/sh

readable_files=0
for filename in "$@"; do
    if test -f "$filename"; then
        readable_files=$(( readable_files + 1 ))
    fi
done

echo "${readable_files}"