pwd(n) Tcl Built-In Commands pwd(n)

pwd - Return the absolute path of the current working directory

pwd

Returns the absolute path name of the current working directory.

Sometimes it is useful to change to a known directory when running some external command using exec, but it is important to keep the application usually running in the directory that it was started in (unless the user specifies otherwise) since that minimizes user confusion. The way to do this is to save the current directory while the external command is being run:
set tarFile [file normalize somefile.tar]
set savedDir [pwd]
cd /tmp
exec tar -xf $tarFile
cd $savedDir

file(n), cd(n), glob(n), filename(n)

working directory
Tcl