Shell if "-z"

If -z in bash

The -z flag causes test to check whether a string is empty. 
Returns true if the string is empty, false if it contains something.

Shell if "-z"

# Returns true if string empty.
# E.G: file.txt does not exist

EXISTS=$(cat file.txt 2> /dev/null)

if [ -z "${EXISTS}" ]; then
	echo "Does not exist"
else
    echo "Exist!"
fi

# Output: 
# Does not exist

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