System Monitoring and Troubleshooting
top
Show running processes, memory/cpu usage. Similar to Task Manager in Windows.
CPU
Show how long it is been running, and load average.
$ uptime
10:11:46 up 7 days, 17:02, 1 user, load average: 1.79, 1.86, 1.79
Get CPU infoy:
$ cat /proc/cpuinfo
CPU count
$ grep -c ^processor /proc/cpuinfo
8
$ python -c "import os; print(os.cpu_count())"
8
Memory
Check free memory (-h for Human-readable`)
$ free -h
total used free shared buff/cache available
Mem: 5.7G 3.8G 457M 74M 1.5G 1.5G
Swap: 5.9G 102M 5.8G
$ free -m uses MiB as unit.
Check /proc/meminfo
$ cat /proc/meminfo
MemTotal: xxxx kB
MemFree: xxxx kB
...
Show sum of memory usage
$ ps aux | awk '{sum +=$4}; END {print sum}'
Virtual memory stats:
$ vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
1 0 105052 385116 114148 1433576 0 1 13 129 145 6 23 25 52 0 0
Disk
Use lsblk:
$ lsblk
To show filesystem type: lsblk -f.
List mounted file systems and usage (-h for "human-readable")
$ df -h
$ df -Th
du can be used to estimate file space usage.
$ du -d1 # depth 1
$ du -s # sum
$ du -h # human-readable
Check Partitions
$ cat /proc/partitions
Check /sys/block
$ cat /sys/block/dm-0/queue/rotational
- RO=0 SSD
- RO=1 HDD
Processes: ps and pstree
Show processes
$ ps
List processes has "cron" in their names:
$ ps aux | grep -i cron
ps -aux means show all processes for all users.
Show the forest of processes:
$ ps aux --forest
Show in tree view
$ pstree
Networking
Read more: Linux Networking
Hardware
lsusb: lists attached USB deviceslspci: lists PCI deviceslshw: list hardwaredmidecode: lists BIOS and other hardware
OS / Software / Env
Linux Kernel and Distro
Check Linux Kernel version
$ uname -r
$ cat /proc/sys/kernel/osrelease
Check Linux distro name and version:
$ lsb_release -a
$ cat /etc/os-release
$ cat /etc/issue
Check GNOME version:
$ cat /usr/share/gnome/gnome-version.xml
$ gnome-shell --version
Check current desktop environment:
$ echo $XDG_CURRENT_DESKTOP
Cinnamon
Check if You are Using Wayland or Xorg?
# if using Wayland
$ echo $XDG_SESSION_TYPE
wayland
# if using x11
$ echo $XDG_SESSION_TYPE
x11
# if tty
$ echo $XDG_SESSION_TYPE
tty
Print platform info
$ python -m platform
Check Runlevel
$ who -r
$ runlevel
List loaded modules
$ lsmod
Check Shell
Check default shell:
$ echo $SHELL
/bin/bash
Check current shell:
$ echo $0
bash
Use ps:
$ ps -p $$
PID TTY TIME CMD
6554 pts/0 00:00:00 bash
ulimit
Per user limit
Check limits
$ ulimit -a
Check limits by PID
$ cat /proc/<pid>/limits
Set limits
$ ulimit -n 64000 -u 64000
nofile: number of open filesnproc: number of processes
Check if your Linux system is physical or virtual machine
$ dmidecode -s system-manufacturer
VMware, Inc.
$ dmidecode | grep Product
$ hostnamectl status
...
Chassis: vm
...
Control Groups
systemd-cgls: Recursively show control group contents