How to properly check if file exists in Bash or Shell (with examples)

In this tutorial I will cover different attributes you can use in bash or shell scripting to check against files and directories. You can use bash conditional expressions with [[ ]] or use test with [ ] to check if file exists.

We will be using bash if and else operator for all the examples so I would recommend you to read: Bash if else usage guide for absolute beginners

 

1. Bash/Shell: Check if file exists and is a regular file

This section shows the examples to check if regular file exists in bash.

 

1.1: Method-1: Using single or double brackets

Using double brackets [[..]]

#!/bin/bash

FILE="/etc/passwd"
if [[ -f $FILE ]];then
    echo "$FILE exists"
else
    echo "$FILE doesn't exist"
fi

Using single brackets [..]

#!/bin/bash

FILE="/etc/passwd"
if [ -f $FILE ];then
    echo "$FILE exists"
else
    echo "$FILE doesn't exist"
fi

 

1.2: Method-2: Using test command

test command is used to check file types and compare values.

#!/bin/bash

FILE="/etc/passwd"
if test -f $FILE; then
    echo "$FILE exists"
else
    echo "$FILE missing"
fi

 

1.3: Method-3: Single line

We can use single or double brackets here in this example. I would recommend always to use double brackets when you are writing one liner code in shell as it minimises the risk of getting warnings on the console when word splitting takes place.

#!/bin/bash

FILE="/etc/passwd"
[[ -f $FILE ]] && echo "$FILE exists" || echo "$FILE missing"

The statement after && will be executed if SUCCESS. If the first condition returns FALSE then statement with || will be executed.

Similarly using test command to check if regular file exists in bash or shell script in single line.

#!/bin/bash

FILE="/etc/passwd"
test -f $FILE && echo "$FILE exists" || echo "$FILE missing"

 

2. Bash/Shell: Check if file exists (is empty or not empty)

To check if the file exists and if it is empty or if it has some content then we use "-s" attribute

 

2.1: Method-1: Using single or double brackets

Check if file exists and empty or not empty using double brackets [[..]]

#!/bin/bash

FILE="/etc/passwd"
if [[ -s $FILE ]]; then
   echo "$FILE exists and not empty"
else
   echo "$FILE doesn't exist or is empty"
fi

Check if file exists and empty or not empty using double brackets [..]

if [ -s $FILE ]; then
   echo "$FILE exists and not empty"
else
   echo "$FILE doesn't exist or is empty"
fi

 

2.2: Method-2: Using test command

Using test command we combine -s attribute to check if file exists and is empty or has some content:

#!/bin/bash

FILE="/etc/passwd"
if test -s $FILE; then
    echo "$FILE exists and not empty"
else
    echo "$FILE doesn't exist or is empty"
fi

 

2.3: Method-3: Single line

We can use both double or single brackets for such one liner but as I said earlier I would recommend using double brackets.

#!/bin/bash

FILE="/etc/passwd"
test -s $FILE && echo "$FILE exists and not empty" || echo "$FILE doesn't exist or is empty"

Similarly with test command we can use && and || operator to check the file in single line command inside our shell script.

#!/bin/bash

FILE="/etc/passwd"
[[ -s $FILE ]] && echo "$FILE exists and not empty" || echo "$FILE doesn't exist or is empty"

 

3. Bash/Shell: Check if directory exists

I hope you know that in Linux everything is a file. So in that way, a directory is also considered to be a file. We can use "-d" attribute to check if a directory exists in shell programming.

 

3.1: Method-1: Using double or single brackets

We can use -d attribute within single [..] or double brackets [[..]] to check if directory exists.

#!/bin/bash

DIR="/var/log"
if [[ -d $DIR ]]; then
   echo "$DIR exists"
else
   echo "$DIR doesn't exist"
fi

Similarly we use single brackets in this example to check if the directory is preset within shell script.

#!/bin/bash

DIR="/var/log"
if [ -d $DIR ]; then
   echo "$DIR exists"
else
   echo "$DIR doesn't exist"
fi

 

3.2: Method-2: Using test command

In this example we will use test command to make sure if directory is present or not before we perform certain task.

#!/bin/bash

DIR="/var/log"
if test -d $DIR; then
    echo "$DIR exists"
else
    echo "$DIR doesn't exist"
fi

 

3.3: Method-3: Single line

In this example we will use single and double brackets in single line form to check for the directory. The statement after && operator will be executed if the first condition is TRUE and if it is FALSE the || condition's statement will be executed.

#!/bin/bash

DIR="/var/log"

[[ -d $DIR ]] && echo "$DIR exists" || echo "$DIR doesn't exist"

I would recommend using [[..]] instead of [..] for such one liner codes in shell programming.

Similarly with && and || we can use test command to check if directory exists

#!/bin/bash

DIR="/var/log"

test -d $DIR && echo "$DIR exists" || echo "$DIR doesn't exist"

 

4. Bash/Shell: Check if directory exists (empty or not empty)

There are no shell attributes as I have used in all other examples and scenarios in this tutorial. But we do have some hacks which we can use to check if directory is empty or not- empty.

 

4.1: Method-1: List the directory content and verify

In this example we will list the content of the directory, suppress the output and then based on the exit code check if the directory is empty or contains some content

#!/bin/bash

DIR="/tmp"
if ls -1qA $DIR | grep -q . ; then
    echo "$DIR is not -empty"
else
    echo "$DIR is empty"
fi

We can also reverse this by putting a NOT (!) condition. So it would look like:

#!/bin/bash

DIR="/tmp"
if ! ls -1qA $DIR | grep -q . ; then
    echo "$DIR is empty"
else
    echo "$DIR is not-empty"
fi

The output would be same in both the example scripts.

 

4.2: Method-2: Using find command

We can use find command and then suppress the output to check if the target directory has some content or not.

#!/bin/bash

DIR="/tmp"
if find -- "$DIR" -prune -type d -empty | grep -q . ; then
    echo "$DIR is empty"
else
    echo "$DIR is not-empty"
fi

 

4.3: Method-3: List the content

Again as I said since there is no easy way to check if a directory is empty or not using some attributes, we will list the content of the directory. If you get no output then the directory is empty or else not empty

#!/bin/bash

DIR="/tmp"
if [[ -z "$(ls -A -- "$DIR")" ]] ; then
    echo "$DIR is empty"
else
    echo "$DIR is not-empty"
fi

 

5. Bash/Shell: List of attributes to test file

Similarly there are many more attributes which you can use with shell scripts to check for different file types, such as symbolic links, file permissions etc.

AttributesWhat it does?
-a FILETrue if FILE exists
-b FILETrue if FILE exists and is a block special file.
-c FILETrue if FILE exists and is a character special file.
-d FILETrue if FILE exists and is a directory.
-e FILETrue if FILE exists
-f FILETrue if FILE exists and is a regular file
-g FILETrue if FILE exists and its set-group-id bit is set
-h FILETrue if FILE exists and is a symbolic link
-k FILETrue if FILE exists and its "sticky" bit is set
-p FILETrue if FILE exists and is a named pipe (FIFO)
-r FILETrue if FILE exists and is readable
-s FILETrue if FILE exists and has a size greater than zero
-u FILETrue if FILE exists and its set-user-id bit is set
-w FILETrue if FILE exists and is writable
-x FILETrue if FILE exists and is executable
-G FILETrue if FILE exists and is owned by the effective group id
-L FILETrue if FILE exists and is a symbolic link
-N FILETrue if FILE exists and has been modified since it was last read
-o FILETrue if FILE exists and is owned by the effective user id
-S FILETrue if FILE exists and is a socket
FILE1 -ef FILE2True if FILE1 and FILE2 refer to the same device and inode numbers
FILE1 -nt FILE2True if FILE1 is newer (according to modification date) than FILE2, or if FILE1 exists and FILE2 does not
FILE1 -ot FILE2True if FILE1 is older than FILE2, or if FILE2 exists and FILE1 does not

 

Conclusion

In this tutorial I shared brief examples of test operators to check for files and directories. You can use any attribute from the table I have shared to enhance your script execution with proper tests.
Lastly I hope the steps from the article to check if file exists or not on Linux was helpful. So, let me know your suggestions and feedback using the comment section.

1 thought on “How to properly check if file exists in Bash or Shell (with examples)”

Leave a Comment

Please use shortcodes <pre class=comments>your code</pre> for syntax highlighting when adding code.