2024-08-11

linux tips

  • info coreutils
  • try to open manual pages for programs or configuration files you want to learn about. example: man locale.conf

  • keybindings on the terminal

    • ctrl+l clear screen
    • ctrl+c quit process, sends the sigint signal
    • ctrl+d exit
  • for ensuring permissions one may create, and regularly run, a script where the desired filesystem permissions are applied with commands like chmod. unanticipated permission changes are otherwise unlikely to be noticed
  • software list

reading live updates from logfiles and other text files

tail -f displays lines from the end of files and continues to display live future updates - so you can wait and see updates in real-time

tail -f /var/log/mylogfile

-n specifies the number of last lines to show at first

tail -n 400 -f /var/log/mylogfile

it can be filtered

tail -f |grep myfilterstring

live updates of multiple files:

tail -f /var/log/mylogfile /var/log/another-file /var/log/and-another-file

regular task execution, task scheduling with cron

cron configuration format

see here

example line

0 */12 * * * /usr/bin/redmine-update-repositories
  • "" means "every". so that " 3" would mean "every minute at hour 3"
  • "*/2" means "each 2"

installation of dcron

su root
# dcron is one of the simpler implementations
pacman -S dcron
systemctl enable crond
# remove the included preset jobs and directories - /etc/cron.daily and the like
crontab -d && rmdir /etc/cron*
mkdir /etc/cron.d
# create rules in cron job files
nano /etc/cron.d/myscript
systemctl start crond

crond sends the standard output from jobs per mail. you may not want this, so edit "/etc/conf.d/crond" and add "-m off" to the arguments. "systemctl status crond" shows log and error information