Dtyjlui

I downloaded Lubuntu 18.04 iso file into my flash drive and make the flash drive into a bootable device.

I inserted the flash drive into a laptop and booted into Lubuntu without actually installing it.

If I need some program not already in the Lubuntu 18.04 iso file, do I need to actually install Lubuntu on the laptop?
Is it possible to install some programs like google chrome browser without actually installing Lubuntu on the laptop?

Thanks.

Which one below is the limit on the total sizes of the programs that I can install?

$ df -h

Filesystem      Size  Used Avail Use% Mounted on

udev            1.7G     0  1.7G   0% /dev

tmpfs           340M  1.4M  338M   1% /run

/dev/sdb        1.1G  1.1G     0 100% /cdrom

/dev/loop0      968M  968M     0 100% /rofs

/cow            1.7G  367M  1.3G  22% /

tmpfs           1.7G   32M  1.7G   2% /dev/shm

tmpfs           5.0M  4.0K  5.0M   1% /run/lock

tmpfs           1.7G     0  1.7G   0% /sys/fs/cgroup

tmpfs           1.7G  4.0K  1.7G   1% /tmp

tmpfs           340M   20K  340M   1% /run/user/999

Yes.

However note that the / fs (file-system) used by 'live-mode' is created in memory & is a set size (the amount of memory allocated is fixed at boot-time and cannot be adjusted during operation). It can fill up if you add too many programs, or updates & your system can become unstable (primarily slow, but also unable to write to / as out-of-space). You'll unlikely reach this in testing the system, but it can be reached if you try & use it as if it's an installed system.

I've been doing QA-tests on Lubuntu 19.04 system(s) last 90+ minutes with no issues, even added apps for one part of test & didn't expect issues. But I was using a daily live. I'd expect a 18.04 (~9 months old) to be slightly different, as adding apps to that may require/cause updates to libs/packages that chew far more space than the single app installed (the 19.04 daily being different as it was created <24 hours ago & I'd expect less library changes even though [active] development release). These deps. need to be considered, but it's still predictable. If I add apps on a live system, I always use terminal so I can assess the dependencies being pulled in, whether new, or upgrades required & thus how it will effect my running system.