Determine whether a file exists or not in Bash
David Y.
—The Problem
How can I determine whether a file exists in Bash? Conversely, how can I test that it does not exist?
The Solution
We can check whether a file exists using the test command-line utility:
if test -f /path/to/file; then echo "File exists." fi
To check whether a file does not exist, we can negate the condition with the NOT logical operator, !:
if ! test -f /path/to/file; then echo "File does not exist." fi
Because the test command is used frequently in Bash expressions, we can write it as [] rather than typing out test:
if ! [ -f /path/to/file ]; then echo "File does not exist." fi
The -f flag tests whether the provided filename exists and is a regular file. To test for directories instead, we can use the -d flag. To test for both files and directories, we can use the -e flag.
More information about test can be found on its manual page, accessible by typing man test into the terminal.
Further Reading
If you’re looking to get a deeper understanding of how Bash application monitoring works, take a look at the following articles:
- Syntax.fmListen to the Syntax Podcast
- ResourcesWhat is Distributed Tracing
- Listen to the Syntax Podcast
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