How to Check if a File Exists in Bash – Simply Explained

Why Do We Check Files in Bash?

When writing a Bash script, you often work with files or folders. Before trying to read, copy, or edit them, you should first check if file exists in Bash. Doing this ensures the file or directory is really there and prevents your script from breaking or showing errors.

Ways to Check in Bash

There are several ways to check if file exists in Bash. The most common options are:

• test EXPRESSION
• [ EXPRESSION ]
• [[ EXPRESSION ]]

All of these can be used for file checks, but [[ ]] has more features and works only in Bash, while [ ] and test are more universal and portable.

File Test Flags

Flag    What It Checks
-e      Any kind of file or directory
-f      A regular file (not a folder or special file)
-d      A directory
-r      File is readable
-w      File is writable
-x      File is executable
-L      A symbolic link (shortcut to another file)
-s      A file that is not empty

Examples Explained

Check if any file or folder exists

if [ -e "$FILE" ]; then
  echo "It exists"
fi

This checks if something is there, whether it is a file or a folder.

Check if it is a regular file

if [ -f "$FILE" ]; then
  echo "It is a file"
fi

This makes sure the path is a normal file and not a folder.

Check if it is a directory

if [ -d "$DIR" ]; then
  echo "It is a directory"
fi

This checks only for folders.

Check file permissions

if [ -r "$FILE" ]; then
  echo "You can read this file"
fi

if [ -w "$FILE" ]; then
  echo "You can write to this file"
fi

if [ -x "$FILE" ]; then
  echo "You can run this file"
fi

These tests confirm whether the file can be read, edited, or run as a program.

Check if a file does not exist

if [ ! -f "$FILE" ]; then
  echo "The file is missing"
fi

The exclamation mark means “not”. This checks if the file is absent.

Check more than one file

if [ -f "$FILE1" ] && [ -f "$FILE2" ]; then
  echo "Both files exist"
fi

This makes sure that two files are present before running further commands.

Conclusion

In Bash, checking if a file or directory exists is simple once you know the flags. Use -e for anything, -f for regular files, and -d for folders. Add checks for read, write, or execute permissions when needed. Always put the file name inside quotes to avoid problems with spaces. If you want to test for something missing, use !. With these methods, your Bash scripts will be much safer and easier to manage.