Bash get basename of filename or directory name

Bash Get Basename of Filename or Directory Name

To extract filename and extension in Bash use any one of the following method:

1. basename /path/to/file.tar.gz .gz – Strip directory and suffix (extension) from filenames.
2. ${VAR%pattern} – Remove file extension.
3. ${VAR#pattern} – Delete from shortest front pattern.
4. awk or sed – Use awk or sed text processing tool to the last part of a path (basename).

Understanding file paths in Linux

Let us take the example of the /home/vivek/foo.tar.gz file:

• /home : This is the first directory in the path. The leading / indicates that this is an absolute path, meaning it starts from the root directory of the filesystem. The path itself is a directory. A directory is nothing but a collection for other files and directories.
• /vivek : This is a subdirectory within the path directory. So, vivek is nested inside path.
• /foo.tar.gz : This is the name of a file. Let’s look at the extension or suffix:
• .tar.gz : This is a common file extension (suffix) indicating a compressed tar archive.
• .tar : This part means a “tape archive.” The tar command is used to combine multiple files and directories into a single archive file, you know like bundling things together for backups or emailing them.
• .gz : This part signifies that the .tar archive has been compressed using the gzip compression program. Gzip reduces the file size. So it will be easier to email or upload it somewhere else using the ftp.

Let us see explore example in bash to get basename of filename.

Bash get filename and extension

To just get filename from a given path. Type the following commands at the CLI:
$ FILE="/home/vivek/lighttpd.tar.gz"
$ echo "The absolute path is $FILE"
# Now print just filename from the absolute path
$ basename "$FILE"
# How about store that info into a shell variable?
$ f="$(basename -- $FILE)"
$ echo "Just filename is $f"

The basename with spaces in a bash script

Sometimes, our file names have whitespace names, and it will create problems in your scripts or commands. For example:

FILE_NAME='/home/vivek/this is a long file name   .txt'
echo "$FILE_NAME"
 
# try basename now and you will get an error #
basename $FILE_NAME
 
# OR #
basename -- $FILE_NAME

Outputs:

basename: missing operand
Try 'basename --help' for more information.

Hence, to deal with filenames with spaces put double quote around CLI arg i.e. “$FILE” or “$FILE_NAME”. For example:

FILE="/path/to  dir  1/foo.txt"
f=$(basename -- "$FILE")
echo "$f"

Try the following examples to extract the basename i.e. the last part of a path in Bash CLI:
$ my_file='/home/vivek/Documents/resume.pdf'
$ basename "$my_file"
Outputs

resume.pdf

Let us just get filename without suffix (extension):
$ pic="/home/vivek/bday-photo.jpg"
$ basename "$pic" .jpg
Outputs:

bday-photo

Try one more example to print your directory name:
$ my_dir="/home/vivek/projects/app1"
$ basename "$my_dir"
Outputs:

app1

The basename command is the most simple and recommended way for all Linux or Unix shell users. But bash offers some other syntax, too. Let’s see them.

Get filename without using basename command

The syntax is as follows for a parameter expansion:
$ FILE="/home/vivek/lighttpd.tar.gz"
$ printf "%s\n" "${FILE##*/}"
The real magic happens when you use "${FILE##*/} a parameter expansion that uses pattern removal. Let me break down that part for ease of understanding:

• ${FILE} : The FILE variable. This is a full (absolute) path to a file.
• ##*/ : This is the pattern being removed.
• # : This symbol, when doubled (##), means “remove the longest matching prefix pattern.” The pattern is defined next as */.
• */ : This is the pattern itself. It matches any string of characters (*) followed by a forward slash (/). In other word, it matches everything up to and including the last forward slash. Thus you end up getting only the filename itself.

Here is another example to get basename of filename or dir name under Linux or Unix-like systems:
$ url="https://www.cyberciti.biz/files/mastering-vi-vim.pdf"
$ echo "${url##*/}"

Basename a file with spaces using bash

Try the following examples (note the $input path has “App Server 2“):
$ input="/home/vivek/project/App Server 2/archive.jar"
$ f="${input##*/}"
$ echo "FULL PATH : $input"
$ echo "FILE : $f"
Outputs:

FULL PATH : /home/vivek/project/App Server 2/archive.jar
FILE : archive.jar

Get running script name using bash parameter

The $0 will provide full path for currently running script. To extract that name only:

Bash get a file extension

Try the following examples:
$ FILE="/home/vivek/lighttpd.tar.gz"
$ echo "${FILE#*.}" # print tar.gz
$ echo "${FILE##*.}" # print gz
$ ext="${FILE#*.}" # store output in a shell variable
$ echo "$FILE has $ext" # display it

Extracting the basename (the last part of a path) in Bash using awk

The syntax is simple:

# define path using $my_path variable
my_path="/home/vivek/Videos/youtube-01-01-2018.mp4"
# Now use awk to print 'youtube-01-01-2018.mp4'
awk -F/ '{print $NF}' <<<"$my_path"
 
# or  #
echo "$my_path" | awk -F/ '{print $NF}'

How to get the basename from the full filename path in bash

Use any one of the following syntax:
$ file="/home/vivek/.gpass/passwd.enc"
$ basename "$file"
$ echo "${file##*/}" # bash syntax
Let us just get the first part of the $file when you know that .enc is extension:
$ file="/home/vivek/.gpass/passwd.enc"
$ basename "$file" .enc
In this following example, I’m not using basename command. It is bash only syntax and when file extension is .enc, type:
$ t="/path/to/dir 1/filename.enc"
$ t="${t%.enc}"
$ echo "$t"

Script example to extract filename and extension in Bash

Try the following shell script:

A note about weird issues

Based on my years of experience in shell scripting, there are two edge cases where your bash script will fail. Let us document them for safety reasons.

• Handling spaces : If your filenames or directory names might contain spaces, enclosing them in double quotes (e.g., basename -- "$file") is crucial.
• Trailing slashes : Be aware that basename might behave differently on different Unix or Linux variant with trailing slash paths (e.g., /path/to/dir1/). Consider handling this case separately if it’s relevant to your needs. This is more of user input issue and basename variant.

Conclusion

You just learned how to get the basename and extension from the full filename when using Bash shell running on a Linux or Unix-like system. For more info see the following dirname command/basename command documentation using the help command or info command/man command:
$ man bash
$ info bash
$ man basename

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