$DIRSTACK if it is non-null or $PWD (the current directory) if it is null.
Table 4.1: Substitution Operators... entially the opposite of basename: it returns the directory prefix only. It is equivalent to the Korn shell e... join. Given a filename like /home/myplace/a.data.directory/a.filename.txt which we'll call $f you could use ... o see output like:
/home/myplace/a.data.directory
a.filename.txt
a.filename
Notice