How do I tell if a file does not exist in bash?

Question

I've used the following script to see if a file exists:

#!/bin/bash
FILE=$1

if [ -f $FILE ];
then
   echo "File $FILE exists."
else
   echo "File $FILE does not exist."
fi

What's the correct syntax to use if I only want to check if the file does not exist?

#!/bin/bash
FILE=$1

if [ $FILE does not exist ];
then
   echo "File $FILE does not exist."
fi

Answer 1

Bash has a "not" logical operator, which is the exclamation point (similar to many other languages). Try this:

if [ ! -f /tmp/foo.txt ]
then
    echo "File not found!"
fi

Answer 2

You can negate an expression with "!":

#!/bin/bash
FILE=$1

if [ ! -f $FILE ]
then
    echo "File $FILE does not exists"
fi

The relevant manpage is "man test".

Answer 3

if [[ ! -a $FILE ]]; then
    echo "$FILE does not exist!"
fi

Also, it's possible that the file is a broken symbolic link. If you want to catch that you should:

if [[ ! -a $FILE ]]; then
    if [[ -L $FILE ]]; then
        echo "$FILE is a broken symlink!"
    else
        echo "$FILE does not exist!"
    fi
fi

Answer 4

I've found this list of bash conditional statements very useful.

Answer 5

If you type "man test" it will show you all the syntax for the "[ ]" (test) in bash.

Answer 6

you can use -z , eg

if [ -z `which grep` ] ;then echo "Missing grep"; fi