File existence checks in Bash Scripting - Cheat Sheet & Quick Revision

Recall & Review

beginner

What command checks if a file exists in a bash script?

Use the test command with -e flag: if [ -e filename ]; then checks if the file named 'filename' exists.

beginner

What does the -f flag check in a bash file test?

The -f flag checks if the file exists and is a regular file (not a directory or special file).

beginner

How do you check if a directory exists in bash?

Use -d flag: if [ -d directoryname ]; then checks if 'directoryname' exists and is a directory.

intermediate

What is the difference between -e and -f in bash file tests?

-e checks if a file or directory exists. -f checks if a regular file exists (not directory).

beginner

Write a simple bash script snippet that prints 'File found' if a file named 'data.txt' exists.

if [ -e data.txt ]; then
  echo "File found"
else
  echo "File not found"
fi

Which bash test flag checks if a file exists regardless of type?

A -f

B -e

C -d

D -x

The -e flag checks if a file or directory exists, regardless of type.

What does the -d flag check in bash?

A If a file is executable

B If a regular file exists

C If a directory exists

D If a file is empty

The -d flag checks if the given path exists and is a directory.

What will this script print if 'myfile' does not exist?

if [ -f myfile ]; then echo "Found"; else echo "Not found"; fi

A Found

B Nothing

C Error

D Not found

Since 'myfile' does not exist, the condition fails and 'Not found' is printed.

Which test flag would you use to check if a file is executable?

A -x

B -r

C -w

D -e

The -x flag checks if the file is executable.

What does this script check?

if [ -e /tmp ]; then echo "Exists"; fi

A If /tmp exists (file or directory)

B If /tmp is a directory

C If /tmp is a regular file

D If /tmp is executable

The -e flag checks if the path exists, whether file or directory.

Explain how to check if a file exists in a bash script and what flags you can use for different file types.

Think about the test command and its flags.

Write a bash script snippet that checks if a directory named 'backup' exists and prints a message accordingly.

Use the -d flag inside an if condition.