unix

Second Argument to basename

Wed Nov 23, 2016

It is quite common knowledge that the basename command is used to get just the file name without its full path.

> basename /home/$USER/file.txt
file.txt

But what wasn’t common knowledge, at least to me, was that basename also accepts a second argument ..

That argument is used to specify the trailing string to be removed from first argument.

From man basename, we get

DESCRIPTION
        Print NAME with any leading directory components removed.  If
        specified, also remove a trailing SUFFIX.

 EXAMPLES
        basename /usr/bin/sort
               Output "sort".

        basename include/stdio.h .h
               Output "stdio".

In other words, with the second argument set to the file’s extension, basename returns the file name without the full path and without the extension.

> basename /home/$USER/file.txt .txt
file

I came across this feature of basename when I wanted to create this tcsh alias:

# Usage: md2 html file.md # Converts file.md (markdown) to file.html
#        md2 pdf file.md # Converts file.md (markdown) to file.pdf
#        md2 docx file.md # Converts file.md (markdown) to file.docx (Word)
alias md2 'pandoc \!:3* \!:2 -o `basename \!:2 .md`.\!:1'