I'm new to Ubuntu, and I've been a bit confused about where to install new programs...

The answer here says:

If the program needs to create a folder, then /usr/local is the directory of choice; according to the FHS:

The /usr/local hierarchy is for use by the system administrator when installing software locally.

Furthermore, most references I've read (e.g. here) say that the root partition should be ~30 GB.

My problem is that if I want to install memory intensive programs (e.g. MATLAB, Mathematica etc.), this really doesn't seem like enough memory for me... I guess I'm just confused as to why the recommendation is so low. Furthermore, this article here (maybe a bit dated?) claims that 25-35% of the root partition should be left as free space for "self-cleaning" purposes. With the OS taking ~6 GB, I just don't understand how this can satisfy any user's needs. Is it because most programs are far below the memory needs of the more memory intensive programs I mentioned?

Any help is greatly appreciated :D

  • What exactly is your question
    – user689314
    Jun 18, 2017 at 6:27
  • I guess I'm just confused about the suggestion to allocate 30 GB to the root partition... is it normal to need a lot more? Also, should I really be installing heavy programs like MATLAB in /usr/local?
    – Atreyu
    Jun 18, 2017 at 7:54
  • Depend on what programs you are going to use.
    – user689314
    Jun 18, 2017 at 7:55

1 Answer 1


Most users install programs via command (sudo apt install firefox) or via software.center|ubuntu.software which automatically installs the program to wherever the .deb file dicated. It's sort of similar with snaps (though they stay as squashfs & aren't installed to your actual filesystem [fs])

Most people's programs aren't that huge; its the data that takes all the space. User data on an ubuntu will generally go to /home/

The /usr is commonly where apt-get|apt|etc will install a program; and its the unix (*nix) default place (ie. historically been put there since '80s if not 1970s)

You can install programs wherever you want! But when you upgrade; remember where you installed it so it can be backed up & restored. I install many things in /usr/local/bin out of habit; but others go inside /home as I find it easier to recover if I have problems (/home is on different drives for many of my systems, at least different partition, thus allows me to replace system drive & clean-install but keep). Also you can choose to use a filesystem that allows growing|shrinking during operation which is more used by servers or mission critical systems.

Note: don't mix up /root & the / directories. /root/ refers to the 'root' user directory (equivalent is /home/root/ if it wasn't a special user), and '/' which is the top or root directory. my "/" directory is on a small 160gb drive; but i've mounted many tb of directories onto it so the partition & drive sizes mean little.

  • Good answer overall, but it makes it sound as if the snap format was free in terms of disk space. It's not; the files still have to go somewhere on the disk. Also, third-party applications that are not distributed via Debian packages traditionally go somewhere in /opt. This directory and /usr/local are similar in purpose, but /opt is for precompiled stuff you get from wherever, whereas /usr/local is for things you compile yourself.
    – Rod Smith
    Jun 18, 2017 at 15:02
  • Thank you for your answer. I was wondering why exactly the FHS recommends installing programs to /usr/local, is there any particular advantage to doing this, over perhaps installing on /home?
    – Atreyu
    Jun 19, 2017 at 8:13
  • I usually have my /home on a different partition (or drive) so if I need to re-install or change OS for any reason, I don't lose my data (inc. programs) in /home (letting it install only to / partition and adding the /home mount to /etc/fstab myself later). Ubuntu unlike some distros is very good at trying to avoid format unless necessary, which is part of why I like /home for stuff whereis can tell you were apps are located, but keeping apps out of /home can simplify backups as programs don't change as much.
    – guiverc
    Jun 19, 2017 at 8:52

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