Using the basename Command in Bash Scripts

In Bash scripting, one of the most common tasks is manipulating file paths—especially when you want to extract just the file name from a full path. That’s where the basename command comes in. While seemingly simple, basename has powerful use cases when used correctly in more complex scripts, automation tools, hosting services, and CI/CD environments.

What Is basename?

The basename command strips the directory path and optionally removes a file extension, leaving only the base name (the final component of a file path).

🔧 Basic Syntax:

✅ Simple Examples:

basename /home/user/docs/report.pdf


basename /home/user/docs/report.pdf .pdf


Why Use basename in Scripts?

Here are just a few examples of real-world scripting needs:

• Logging: Extract the name of a log file being processed.

• Archiving: Append only the filename to a compressed archive.

• Automation: Process batches of files and generate output filenames.

• Pipelines: Extract file names in CI/CD steps.

 Practical Use Cases in Bash Scripts

📁 1. Looping Over Files with Logging

for file in /var/log/*.log; do
name=$(basename "$file" .log)
echo "Processing $name"
# Add further commands like gzip "$file" or tail -n 100
done

This script loops over .log files, extracts the name without extension, and logs each action. basename simplifies filename handling without complex string slicing.

📂 2. Using basename for Dynamic File Paths

Let’s say you’re receiving full paths from user input or another process:

#!/bin/bash
input_path="$1"
filename=$(basename "$input_path")
echo "The file name is: $filename"

Using basename in your script ensures flexibility when working with dynamic file paths, especially in environments like a Linux VPS where logs, config files, and backups may reside in different directories. This makes your script robust regardless of whether it’s passed a full path like /var/log/syslog or a relative file like ./config.txt.

🧪 3. Combining basename with dirname

Use them together to isolate path elements:

#!/bin/bash
path="/etc/nginx/nginx.conf"
echo "Directory: $(dirname "$path")"
echo "Filename: $(basename "$path")"

 Removing File Extensions with basename

If you want to remove known extensions:

basename report-final.txt .txt

⚠️ Note: This only works if the suffix matches exactly. So .txt works, but .TXT or .tar.gz won’t unless explicitly specified.

For multiple extensions, combine basename with other tools:

file="/tmp/data/archive.tar.gz"
filename=$(basename "$file")
clean_name=${filename%%.*}
echo "$clean_name"
# Output: archive

Or:

basename vs Parameter Expansion

While basename is intuitive, it spawns a subprocess. For performance-critical scripts or large loops, prefer pure Bash alternatives:

Bash Native Equivalent:

Remove extension with native Bash:

✅ Faster than calling external basename.

Example: Renaming Files in Bulk

Let’s say you want to prefix all .jpg files with today’s date: