Dirs

Dirs refers to the directory stack used by many Unix-like shells to manage a history of directories visited during a shell session. The feature provides quick navigation between multiple working directories without typing full paths. It is implemented as a set of shell builtins, commonly including dirs, pushd, and popd, in shells such as Bash, Zsh, and KornShell (ksh).

The directory stack stores a sequence of directories, with the current directory at the top. The pushd command adds a new directory to the top of the stack and switches the working directory to it. The popd command removes the top entry from the stack and changes the current directory to the next entry. The dirs command displays the contents of the stack, typically from top to bottom. In some shells, dirs can show a numbered list to facilitate referring to a specific entry, for example using an argument like +N or -N in certain contexts or with options such as -v in Bash.

Usage examples illustrate common workflows: starting from any directory, you can run pushd /etc and then pushd /var/log to push two entries onto the stack and switch to the last directory. Running dirs would show the current stack, and popd would return you to the previous directory on the stack. This mechanism helps researchers, developers, and system administrators navigate between multiple project or log directories efficiently.

Notes on portability: directory stack features are not part of the POSIX sh spec and may vary in implementation. They are widely available in Bash, Zsh, and ksh, but not guaranteed in all shells. When present, they can greatly speed up directory navigation.