Raspberry Pi Reminders

Sep 10, 2026 Robin S

Show temperature of Rasp Pi:

$ cat /sys/class/thermal/thermal_zone0/temp
53692

This means 53.6 degC : i.e. you have to divide by 1000 to get the temp in degC :

BOB=`cat /sys/class/thermal/thermal_zone0/temp`
expr $BOB / 1000    # divide by 1000

to use ‘sar’ for recording system performance:

# apt install sysstat

(optional) set it to run every 5min instead of 10min in /etc/cron.d/sysstat
change ENABLED="false" to “true” in /etc/default/sysstat

# systemctl enable sysstat

# systemctl start sysstat

Then use sar -u or similar , to check it’s working

to use Pi’s serial port :

enable Pi’s UART :

remove the phrase console=serial0,115200 from /boot/cmdline.txt
add enable_uart=1 to /boot/config.txt and reboot Pi.

apt install screen

$ screen /dev/serial0 115200

Ctl-A then k to quit
to scroll back : Ctl-A then Esc ; then use Up and Down arrows to scroll

to find device name of USB stick:

$ lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda           8:0    0 29.8G  0 disk
└─sda1        8:1    0    7G  0 part /media/pi/rootfs
mmcblk0     179:0    0 29.7G  0 disk
├─mmcblk0p1 179:1    0  256M  0 part /boot
└─mmcblk0p2 179:2    0 29.5G  0 part /

mmcblk0 is the Pi’s SD card, so the USB stick is /dev/sda