test statement in shell script

[Maureen Gunkel]

I am modifying an existing script, and I have a statement like this:
if [[ -a filename ]] then ....
I have searched and studied and cannot figure out exactly what it means. The documentation tells me that -a is an 'and' operator, but what is it comparing to? Please help, I like to understand what I'm running!

[Kofi ARTHIABAH · Accepted solution]

Maureen:

That (-a) is the korn shell argument for testing if file exists. It does not exist under bourne shell or c shell.

man ksh

[f. halili]

The "-a" that you are using is used to check an object.
Using "-a" to test an object will test if it exist.
Example:

if [[ -a name_of_filename ]]
then
echo "file exists"
fi

The -a is also the "AND" operator as used in most scripts.

`fnhalili`

[Dan Hetzel]

Kofi,

The -a test operator works in posix shell as well

example:
[[ -a filename ]] && echo "file exists"

man posix-sh

Best regards,

Dan