Linux - Reading summaries Flashcards
(63 cards)
systemd
Utility for activating system resources, server daemons, and other processes at boot time and on a running system.
systemctl start [unit]
Start a service or other systemd unit.
systemctl stop [unit]
Stop a service or other systemd unit.
systemctl reload [unit]
Reload configuration of a service or other systemd unit.
systemctl enable [unit]
Enable a service or other systemd unit to start automatically at boot time.
systemctl disable [unit]
Disable a service or other systemd unit from starting automatically at boot time.
systemctl status [unit]
Check the status of a service or other systemd unit.
systemctl list-dependencies [unit]
List all service units that a specific service unit depends on.
systemctl mask [unit]
Prevent a service unit from running, even to satisfy dependencies.
Service units
Managed by systemd to control individual services.
Socket units
Managed by systemd to control socket-based activation of services.
Path units
Managed by systemd to activate services based on file system events.
File ownership permissions
Three categories: user, group, and other users. Most specific permission applies. User permissions override group permissions, and group permissions override other permissions.
ls -l option
Used with the ls command to expand the file listing to include both file permissions and ownership.
chmod command
Changes file permissions from the command line.
Methods of representing permissions
Two methods: symbolic or octal.
chown command
Changes file ownership. The -R option recursively changes the ownership of a directory tree.
umask command
Displays or sets the default file permissions for newly created files.
Default umask values for Bash
Defined in /etc/login.defs and might be affected by settings in /etc/profile, /etc/bashrc, files in /etc/profile.d, or user’s shell initialization files.
suid, sgid, and sticky bits
Special permissions providing additional access-related features to files.
Process
A running instance of an executable program, with states including running, sleeping, stopped, or zombie.
ps command
Lists processes running on the system.
Terminal Session
Each terminal has its own session, with a foreground process and independent background processes.
jobs command
Displays processes within a terminal session.