Linux Survival Basics
Read-onlyCheck /boot Disk Usage
You need free space and Use% for the boot filesystem.
Command
df -h /bootBefore you run this
System impact: Read-only. Low when scoped to the shown target.
When not to use it: Do not delete kernels from /boot directly.
Expected output
Filesystem size, used, available, Use%, and mountpoint for /boot.
System impact
Read-only. Nothing changes. The command reads current state and prints diagnostic evidence.
Recovery / rollback: no state is changed.
When to use it
Use before kernel package cleanup.
When not to use it
Do not delete kernels from /boot directly.
Example run
Commands shown
These are the commands shown for inspection. Treat them as an example, not proof that your system will behave identically.
df -h /bootdf -h /boot
next steps
Related commands
Check Memory Pressure with free
Linux memory numbers look scary until you know which column matters.
free -h
Take a Memory Pressure Snapshot
Measure memory and swap before changing service limits.
free -h
Find the Files Eating Your Disk
The disk was full, but guessing at folders was the slow part.
find /var -type f -printf '%s %p\n' | sort -nr | head -20
Check systemd Journal Disk Usage
Before deleting random logs, ask journald how much disk it owns.
journalctl --disk-usage
Check Memory Pressure Quickly
See whether memory is actually tight before restarting services.
free -h
next diagnostic step
Where to go from this command
- Boot partition full hub Use when /boot has no space.
Study mapping
Use this as independent command practice: read the notes, predict the output, then compare it with the example before using a real shell.
Independent study support only. No affiliation, endorsement, exam dumps, or real exam questions.