Bash Scripting - How to check If File Exists

In this article, we will write a bash script to check if files exist or not. 

Syntax :

• test [expression]
• [ expression ]
• [[ expression ]]

Here, in expression, we write parameter and file name. Let us see some parameters that can be used in the expression: -

• -f:  It returns True if the file exists as a common ( regular ) file.
• -d: it returns True if directory exists.
• -e: It returns True if any type of file exists.
• -c: It returns True if the character file exists.
• -r: It returns True if a readable file exists.
• -w: It returns True if a writable file exists.
• -x: It returns True if an executable file exists.
• -p: It returns True if the file exists as a pipe.
• -S: It returns True if the file exists as a socket.
• -s: it returns True if a file exists and the size of the file is not zero.
• -L: It returns True if the file of symbolic link exists.
• -g: It returns True if the file exists and hold set group id flag is set..
• -G: It returns True if the file exists and holds the same group id that is in process.
•  -k: It returns True if the file exists and the sticky bit flag is set.

Now, there are some more parameters for comparison between the two files.

• -ef: It returns True if both files exist and indicate the same file. 

Example : 

FirstFile -ef SecondFile

• -nt: It returns True if FirstFile is newer than Secondfile.

Example :

FirstFile -nt FileOld

• -ot: It returns True if FirstFile is older than SecondFile.

Example: 

FirstFile -ot SecondFile

Let us take some examples based on syntax :

• [ expression ]: First, create a file named " FirstFile.sh " and write the following script on it

#!/bin/bash

# using [ expression ] syntax and in place 
# of File.txt you can write your file name 
if [ -f "File.txt" ]; 
then

# if file exist the it will be printed 
echo "File is exist"
else

# is it is not exist then it will be printed
echo "File is not exist"
fi

Now save and run the file using the following command

$ chmod +x ./FirstFile.sh
$ ./FirstFile.sh

Output : 

Note: As the " File.txt " is present in the system. So, it printed " File is exists ".

• test [expression]: Now, modify the above script in " FirstFile.sh " as follows

#!/bin/bash

# using test expression syntax and in place 
# of File2.txt you can write your file name
if test -f "File2.txt" ;
then

# if file exist the it will be printed 
echo "File is exist"
else

# is it is not exist then it will be printed
echo "File is not exist"
fi

Now, again save and run the file using the following command

$ chmod +x ./FirstFile.sh
$ ./FirstFile.sh

Output :

Note: As the " File2.txt " is not present in the system. So, it printed " File is not exist ".

• [[ expression ]]: Again modify the above script in " FirstFile.sh " as follows

#!/bin/bash

# using [[ expression ]] syntax and in place 
# of File3.txt you can write your file name
if test -f "File3.txt" ;
then

# if file exist the it will be printed 
echo "File is exist"
else

# is it is not exist then it will be printed
echo "File is not exist"
fi

Now, again save and run the file using the following command

$ chmod +x ./FirstFile.sh
$ ./FirstFile.sh

Output :

Note: As the " File3.txt " is present in the system. So, it printed " File is exist ".

Let us see an example based on parameters:

• Using -d parameter: Create a file named " FirstDir.sh " and write the following script in it

!/bin/bash
if [[ -d "GFG_dir" ]] ; # Here GFG_dir
 is directory and in place of GFG_dir you can write your Directory name
then
echo "Directory is exist" # If GFG_dir exist then it will be printed
else
echo "Directory is not exist" # If GFG_dir is not exist then it will be printed
fi

Now Save and run the file using the following command

$ chmod +x ./FirstDir.sh
$ ./FirstDir.sh

Output :

Note: As the " GFG_dir " is present in the system. So, it printed " Directory is exist ".

Similarly, you can use -f , -e , -w , -r , -c ,etc. ( according to their uses ) in place of -d for checking the existence of different types of files.

Let us see an example based on a comparison of two files :

• Using -nt parameter

Create a file name " Comparison_File.sh " and write the following script 

#!/bin/bash

# New_file.txt and Old_File.txt are names of two files.
if [[ "New_File.txt" -nt  "Old_File.txt" ]] ;
then

# This will be printed if Condition is true
echo "New_File.txt is newer than Old_File.txt" 
else

# This will be printed if Condition is False
echo "New_File.txt is not newer than Old_File.txt"
fi

Now Save and run the file using the following command

$ chmod +x ./Comparison_File.sh
$ ./Comparison_File.sh

Output :

Note: As both files are present in the system and " New_File.txt " is newer than " Old_File.txt "

Let us see the example " Check if File does not exist" :

Create a file named " Check_Exist.sh " and write the following script in it 

#!/bin/bash

# using ! before -f parameter to check if 
# file does not exist
if [[ ! -f "GFG.txt" ]] ;
then

# This will printed if condition is True
echo "File is not exist"
else

# This will be printed if condition is False
echo "File is exist"
fi

Now Save and run the file using the following command

$ chmod +x ./Check_Exist.sh
$ ./Check_Exist.sh

Output :

Note:  " GFG.txt " is not present in the system. So, it will print "File is not exist"

Let us see an example without using the If-else  condition :

Create a file named " Geeks_File.sh " and write the following script in it

#!/bin/bash

# If File exist then first statement will be
# printed and if it is not exist then 2nd
# statement will be printed.
[ -f "GFG_File.txt" ] && echo "File is exist" || echo "File is not exist"

Now Save and run the file using the following command

$ chmod +x ./Geeks_File.sh
$ ./Geeks_File.sh

Output : 

Note: As the " GFG_File.txt " is present in the system. So, it printed " File is exist ".

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Article Tags :

• Linux-Unix
• Bash-Script