Filename from pathname excluding (unknown) extension

Question

Having a pathname it is possible to extract its filename, excluding its apriori known extension, with basename:

$ pathname="/home/paulo/paulo.pdf"
$ printf "%s\n" "$(basename $pathname .pdf)"
paulo

But if the extension is not known how can this be done?

Answer 1

In the zsh shell:

$ pathname=/home/paulo/paulo.pdf
$ printf '%s\n' $pathname:t:r
paulo

• The :t modifier ("tail") extracts the last pathname component in $pathname (it works like basename).
• The :r modifier ("root", I suppose) extracts the bit of the filename up to the extension, if there is one. The extension is the part of the filename that occurs after the last dot. This means that you would get an empty result for filenames like .zshrc.

The other related modifier are

• :h ("head"), which works like dirname, and
• :e ("extension"), which extracts the extension only.

Answer 2

You can use the shell’s parameter expansion modifiers:

$ pathname="/home/paulo/paulo.pdf"
$ filename=${pathname##*/}
$ printf "%s\n" "$filename"
paulo.pdf
$ basename=${filename%.*}
$ printf "%s\n" "$basename"
paulo

${pathname##*/} is expanded to the contents of pathname, minus the longest prefix matching */, i.e. the full path (if there is one). ${filename%.*} is expanded to the contents of filename, minus the shortest suffix matching .*, i.e. the file’s extension (if there is one).

Note that this only removes the last filename component introduced by a dot; so paulo.tar.gz would become paulo.tar, not paulo. Strictly speaking the extension is .gz (it’s a compressed file, which happens to be a tarball; the .tar extension only becomes really meaningful once the file has been extracted).

This also fails to work correctly for extension-less dot-files, e.g. .bashrc or .zshrc; basename ends up empty. Default values can be used to handle that:

$ pathname="/home/paulo/.zshrc"
$ filename=${pathname##*/}
$ printf "%s\n" "$filename"
.zshrc
$ basename=${filename%.*}
$ printf "%s\n" "$basename"

$ printf "%s\n" "${basename:-$filename}"
.zshrc

Answer 3

This should do what you want:

pathname="/home/paulo/paulo.pdf"
printf "%s\n" "$(basename $pathname)" | sed "s/\..*$//"