To use a single Squish installation from multiple users the Squish IDE (which is based on Eclipse - https://eclipse.org) needs to be set up in a special way. This is generally explained in the section Eclipse multi-user installs of the Eclipse documentation.
To set the Squish IDE up like this requires the following steps:
Install Squish - but do not let the installer start the Squish IDE, and do not start it yourself.
Using the same user that was used to install Squish, execute the following in a shell/command prompt:
Set the file system access rights to the folder
squish_dir bin/ideand all contained files and folders recursively to be read-only for all users (
chmod 660 -R squish_dir/bin/ide). This should make the Squish IDE automatically use a configuration folder in the home directory of each individual user who launches it.
The only caveat may be that one needs to make sure that none of the users has administrative rights, as that may alter the file system access rights again.