Having downloaded archives of Sage,
Firefox, and Thunderbird from their respective websites on Trisquel 6.0, neither clicking the appropriate shell script nor executing a command to run the programs will open them. Looking at the files' permissions, they are indeed executable.
Edit: Firefox and Thunderbird have now mysteriously started working; Sage, however, remains inoperable. Having downloaded it from the first link on this page, extracted it to my desktop (where Firefox and Thunderbird run just fine), opened the folder in the terminal and run the command "sage" (as there is an executable by that name in the folder) I receive the error:
bash: sage: command not found. Yet
ls -l shows that the files are known to exist and be executable.
Edit #2: I only thought Firefox and Thunderbird were working. I was actually running the versions I already have installed. Running Firefox and/or Thunderbird with
./[executable] gives the error
libxul.so: cannot open shared object file: No such file or directory Couldn't load XPCOM.