These are the names of system environment variables that Plesk sets up on Windows to simplify access to its directories for administrators and scripts.
Variables exported by Plesk include the following:
%plesk_dir%-- path to Plesk installation directory (e.g., C:\Program Files (x86)\Parallels\Plesk)
%plesk_cli%-- path to directory with Plesk command-line utilities (e.g., C:\Program Files (x86)\Parallels\Plesk\bin)
%plesk_bin%-- path to directory with Plesk backend utilities (e.g., C:\Program Files (x86)\Parallels\Plesk\admin\bin)
%plesk_vhosts%-- path to directory with virtual hosts (e.g., C:\Inetpub\vhosts)
These shorthand paths are mentioned in Parallels Knowledgebase articles and can also be used for quick access to Plesk directories in Command Prompt, Windows Explorer, or the Run dialog. For example:
C:\Users\Administrator>cd "%plesk_dir%" C:\Program Files (x86)\Parallels\Plesk>
Note: Always include paths in double quotes. If a path stored in an environment variable contains a space, commands that use such a variable without quotes will finish with errors, e.g:
C:\Program Files (x86)\Parallels\Plesk>%plesk_cli%\pleskbackup --help 'C:\Program' is not recognized as an internal or external command, operable program or batch file.