Linux Boot Process
Linux Boot Process # Power on # BIOS/UEFI # MBR/GPT # GRUB/GRUB2 # GRUB2 Kernel # initd/systemd # Login #
sysadmin
Linux CLI
Notes # Linux File System File Redirection Bash Expansion Tilde Expansion Command Substitution Strings in Bash File Permissions Shell Prompt Archiving and Backup regex Directory Stack Builtins Bash Variables Resources # The Art of Command Line See also # Data Science at the CLI Awesome Shell
Linux Commands
Linux Commands # adduser alias - Create an alias for a command apropos - Display a list of appropriate commands aspell - Interactive spell checker aspell check textfile Can be used to spell-check specific file types like HTML for example. bc bg - Place a job in the background bzip2 - A block sorting file compressor Similar to gzip but uses different compression algorithm. ...
Linux File System
Linux Filesystem # Linux Directory Structure # FHS Filesystem Hierarchy Standard Common File-Paths # Directory Comments / The root directory /bin Binaries /boot Linux Kernel, initial RAM disk image, boot loader /dev This is a special directory that contains device nodes /etc System-wide config files and init scripts for services /etc/crontab /etc/fstab File system table, lists devices mounted at boot time /etc/passwd Where user accounts are defined /etc/group Where user groups are defined /etc/shadow User’s passwords /home User directories /lib Shared libary files used by core system programs /lost+found Used in case of a partial recovery from a file system corruption event /media Mount points for removalbe media such as USB, CD-ROMs, additional drives /mnt On older Linux systems /mnt is for manually mounted removable devices /opt Optional software /proc Virtual file system maintained by the Linux kernel /root Home directory for root /sbin System binaries /tmp Temporary files created by programs /usr All programs and support files used by regular users /usr/bin Executables installed by Linux Distro /usr/lib Shared libraries for programs in /usr/bin /usr/local Executables not from Linux Distro, usually sysadmin installed /usr/sbin More system administration programs /usr/share All data shared by programs in /usr/bin /usr/share/doc Documentation for packages installed on system /var Where changing data such as databases, spool files, mail, etc /var/log System log files /var/log/messages /var/log/syslog /etc/fstab # Field Contents Description 1 Device Name of device file or label (UUID) associated with device 2 Mount point Directory where device is attached to the file system tree 3 File system type e. ...
Local User Authentication Files
Local User Authentication Files # List of local user auth files and their backups. [root@server1 ~]# ls -l /etc/{passwd,group,shadow,gshadow}* -rw-r--r--. 1 root root 881 Feb 23 15:59 /etc/group -rw-r--r--. 1 root root 873 Feb 23 15:59 /etc/group- ----------. 1 root root 710 Feb 23 15:59 /etc/gshadow ----------. 1 root root 702 Feb 23 15:59 /etc/gshadow- -rw-r--r--. 1 root root 2203 Feb 23 15:57 /etc/passwd -rw-r--r--. 1 root root 2158 Feb 23 15:57 /etc/passwd- ----------. ...
Network Operations and Management
Network Operations and Management # SNMP # 2021-02-06–09-02-01Z–snmp Syslog #
Package Management
Package Management # Red Hat Family # rpm RHEL, CentOS, Fedora, Rocky, Alma # dnf SUSE # zypper Debian Family # dpkg apt Arch Linux Family # pacman
pacman
pacman #
Performance & Optimization
Performance & Optimization # Resources # Explanation of what load averages really means Commands you should run in the first 60 seconds on a misbehaving server In-depth analysis of Linux Performance tools 30 Linux monitoring tools every sysadmin should know Notes # Source Slides from presentation It’s important to have a methodology. ...
PowerShell
PowerShell # Learning PowerShell # Learn Windows PowerShell in a Month of Lunches