Free Space in Broken Ubuntu System | Generated by AI

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Question: In this situation (broken sudo, system low on space after massive CUPS logs, currently booting from Ubuntu live USB), what files or directories in /usr can I safely delete to free up some space?

Answer:

Since you’re already in the live USB environment (or can chroot into the broken system), you have full root access via the live session — this is the perfect time to free space before fixing sudo. The goal is to delete large, non-critical, regeneratable or safely removable data inside /usr without breaking the system further.

Safest and most effective deletions in /usr (from live USB):

  1. The huge CUPS log files (by far the biggest win — likely 200–300 GB)
    These are not in /usr — they are in /var/log/cups/, but since you asked about /usr, I’ll list them anyway as priority #1: 
    sudo rm -rf /mnt/root/var/log/cups/*
# or just the big ones:
sudo truncate -s 0 /mnt/root/var/log/cups/error_log*
sudo truncate -s 0 /mnt/root/var/log/cups/access_log*
sudo truncate -s 0 /mnt/root/var/log/cups/page_log*

  2. Large things actually inside /usr that are usually safe to remove or clear

    • Old cached .deb packages (often 5–30 GB on long-running systems) 
      sudo rm -rf /mnt/root/usr/share/doc/*               # documentation — usually 1–5 GB, safe
sudo rm -rf /mnt/root/var/cache/apt/archives/*.deb  # downloaded packages — very safe, will re-download if needed
sudo rm -rf /mnt/root/var/cache/apt/archives/partial/*
    • Locale data (if you only need English or a few languages) 
      sudo rm -rf /mnt/root/usr/share/locale/{af,am,ar,as,az,be*,bg,bn*,bo*,br*,bs*,ca,cs,cy,da,de*,dz*,el,en_AU,en_CA,eo,es*,et*,eu*,fa*,fi,fr*,ga,gez*,gl*,gu*,haw,he*,hi*,hr,hu*,hy*,id*,is*,it*,ja*,ka*,kk*,km*,kn*,ko*,ku*,ky*,lo*,lt*,lv*,mg*,mi*,mk*,ml*,mn*,mr*,ms*,mt*,my*,nb*,ne*,nl*,nn*,no*,or*,pa*,pl,ps*,pt*,ro*,ru*,rw*,si*,sk*,sl*,sq*,sr*,sv*,sw*,ta*,te*,tg*,th*,ti*,tk*,tl*,tr*,tt*,uk*,ur*,uz*,vi*,wa*,xh*,yi*,yo*,zh*,zu*}

      (Keep only en, zh, your language — this can free 1–4 GB)

    • Man pages and info docs (regeneratable, often 500 MB–2 GB) 
      sudo rm -rf /mnt/root/usr/share/man/*
sudo rm -rf /mnt/root/usr/share/info/*
    • Unneeded icon themes / pixmaps (can be 1–3 GB) 
      sudo rm -rf /mnt/root/usr/share/icons/*             # extreme — removes all icons, only do if desperate
sudo rm -rf /mnt/root/usr/share/pixmaps/*
    • Old kernels (if many are installed — check first) 
      ls -lh /mnt/root/boot/vmlinuz* /mnt/root/boot/initrd.img*
sudo rm -f /mnt/root/boot/vmlinuz-OLDVERSION /mnt/root/boot/initrd.img-OLDVERSION

      (Only delete kernels older than your current one — keep at least the latest + one backup)

    • Snap cache / old revisions (if using snaps — often several GB) 
      sudo rm -rf /mnt/root/var/lib/snapd/cache/*
sudo rm -rf /mnt/root/var/lib/snapd/snaps/*.old   # old snap revisions
    • Python / pip cache (sometimes large) 
      sudo rm -rf /mnt/root/usr/local/lib/python*/dist-packages/*/__pycache__/
sudo rm -rf /mnt/root/root/.cache/pip/*

Quick checklist – run these from live USB (replace /mnt/root with your mount point):

# Highest impact first
sudo du -sh /mnt/root/var/log/cups/               # confirm size
sudo rm -rf /mnt/root/var/log/cups/*

sudo du -sh /mnt/root/var/cache/apt/archives/
sudo rm -rf /mnt/root/var/cache/apt/archives/*.deb

sudo du -sh /mnt/root/usr/share/locale/
# decide if you want to thin it out (see above)

sudo du -sh /mnt/root/usr/share/doc/
sudo rm -rf /mnt/root/usr/share/doc/*

# Check before deleting
sudo du -sh /mnt/root/boot/
# then selectively remove old kernels

Things you MUST NOT delete in /usr (will break system badly):

After freeing space → continue with the chroot + fix sudo steps from the previous message.

If you run sudo du -sh /mnt/root/usr/* | sort -hr | head -20 you will see the actual largest directories and can decide more precisely.

References:

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