System

kernel modules

1 min read · system

Kernel modules live in lib/modules/$(uname -r) Change Load them with 1modprobe ath9k Or remove one with 1modprove uvcvideo The PC's irritating speaker beep can be really annoying. Disable it with: 1modprobe -r pcspeaker Permanently disable a module by blacklisting it in /etc/modprobe.d: 1echo 'blacklist pcspkr' > …

logs

1 min read · system

Basic Keeping track of health problems. Mostly under /var/log/. These logs are created by syslogd (or syslog in earlier distros). Rundown `alternatives.log' has a bunch about other programs installing things around 5 times a day. This includes x-www-browser, which sets the default browser (supposedly - this doesn't …

Make help target

1 min read · system make help

Make your first target 'help' to give an overview of the main targets. Running make help will search for text which starts with ## and show what that target does. 1.PHONY: help 2help: ## Print the help message. 3 @awk 'BEGIN {FS = ":.?## "} /^[0-9a-zA-Z._-]+:.?## / {printf "\033[36m%s\033[0m : %s\n", $$1, $$2}' …

Makefile Graphs

1 min read · system make graph

If you have graph-easy (often in the package perl-graph-easy or similar), you can make a graph from the makefile with make2graph (the package is often called makefile2graph). Start with the command to 'make all targets' (-B), and 'do a dummy run' (-n) with debug into (-d): 1make -Bnd 2make -Bnd | make2graph 3make -Bnd …

Makefile Patterns

1 min read · system make

Using the basic example, you can make a complete backup of all backup files. This file will depend upon everything inside the $(storage_directory). Unlike bash, you can't just say storage_directory/: the pattern must be stated as a 'wildcard'. 1$(storage_directory)/backup.tgz: $(wildcard $(storage_directory)/.md) 2 …

Makefile Workflow

2 min read · system makefiles

Requirements Makefiles Makefiles can quickly become large and confusing. I found these steps keep them easy to understand later and quick to write. 1mkdir blog.rs 2cd !$ 3for x in one two three 4do 5 fortune > posts/$x.md 6done Three Steps Define variables up-front so you know what they all are. Define dependencies …

Makefiles

3 min read · system make

The make system wants to know: What file you want to make, Which other files it depends on, and How to build the file. Start with a basic test-area. 1mkdir make_test ; cd $_ 2printf "%s:\n" README.md > Makefile 3printf "\t%s\n" 'echo "Basic makefile example." > $@' >> Makefile 4make NB: Always tell make how to build …

Managing Groups

1 min read · system

Check which groups you are in, and which are available: 1groups 2cat /etc/group 3column -ts: /etc/group 4grep $USER !$ Remove yourself from all groups, and add yourself back to only mail, audio, and your own group: 1sudo usermod --groups mail,audio,$USER Add yourself to the docker group, if there is one: 1grep docker …

Monitoring

1 min read · system CPU memory

Print the average CPU load over 1 minute, 5 minutes, and 15 minutes: 1watch -d cat /proc/loadavg 2stress="$(cat /proc/loadavg | awk '{print "Usage:" $2"%"}')" Show memory usage in Gibitytes. 1free -g Show low and high gigibtye usage on a line, and repeat the measurement every 5 seconds: 1REP=5 2free --lohi -g -s $REP | …

partitions

3 min read · system

FDisk Basics 1su root 2fdisk /dev/sda m for help. n to make a partition. t to mark the partition type (see IDs below). w to write the changes to the disk. Note the asterisk marking the boot partition. IDs ID Meaning 83 Linux 5 Extended 82 Swap fdisk will not help with a GPT formatted drive. For this, use gdisk, which …