System

$EDITOR

1 min read · system

The System's default text editor can be defined within /etc/profile. It's given the variable EDITOR. Add these lines to /etc/profile.d/custom.sh: 1echo 'export EDITOR=vim' >> /etc/profile.d/custom.sh 2echo 'export VISUAL=$EDITOR' >> /etc/profile.d/custom.sh Then reload that profile with: 1source /etc/profile If you …

android

1 min read · system phone

mtpfs Start Install: 1yay -S simple-mtpfs List available phones: 1simple-mtpfs -l Make a mount point: 1mkdir phone Check your phone, and tell it to allow access to the USB. 1simple-mtpfs --device 1 phone Stop 1fusermount -u phone 2rmdir phone

awk

2 min read · system .csv

Basics See a file's contents: Return full contents of a string: 1awk '{ print }' file Print the first and second column: 1awk '{print$1$2}' Return every line with the word 'the' (like grep): 1awk '/the/{print}' file Print everything containing a lowercase letter: 1awk '/[a-z]/{print}' file Same with numbers [0-9], or …

character-encoding

1 min read · system encoding

Convert a text file from one encoding type to another with: 1iconv -f ascii -t utf8 oldfilename > newfilename Available options are: ISO-8859-15 UTF-8 ASCII Lots more Generate a full list of encoding types available with: 1iconv -l

deduplicate

1 min read · system deduplicate maintenance storage

rdfind: find duplicate files, then delete them, or turn them into links. Ask if a directory has duplicates (rdfind will not delete anything): 1rdfind $dir 2$EDITOR results.txt Replace the duplicated files with hard links. 1rdfind -makehardlinks true $dir

fstab

1 min read · system disk

Basics The ordering of /etc/fstab is disk mount point filesystem type options dump pass Example: 1UUID=877f14e8-4738-46b0-884f-ba330dad1a7d /mnt/biggie ext4 nofail,rw,relatime 0 2 2 3UUID=B21648C416488AF5 /mnt/share ntfs nofail,rw,nosuid,nodev,user_id=0,group_id=0,allow_other,blksize=4096 0 0 5: Dump Ignore this …

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 …