Linux System Administration and Open Source Foundations

Practice flashcards covering Linux commands, package management, file system hierarchy, logging, and system operations based on lecture notes.

Open Source Software Characteristic

One of the 10 points in the open source definition is that users may modify the original code and redistribute the altered version.

Linux Distribution Software

Some distributions, particularly "Enterprise" versions sold for money, include software that is neither open source nor freely redistributable.

VMS

An operating system for minicomputers and mainframes that existed when Linux was created; it was not a common OS on x86 PCs.

DOS

The dominant OS on x86 computers in 1991.

Shareware

A type of software distributed for free that requires payment on the honor system if used; it allows authors to release binary executables without initial payment.

dnf check-update

Updater for Redhat/Fedora systems.

dnf upgrade

Command to upgrade local packages in Redhat/Fedora.

dnf search

Command to search the package repository in Redhat/Fedora.

dnf info

Command to show package information in Redhat/Fedora.

dnf install

Command to install a package in Redhat/Fedora.

dnf erase

Command to remove an rpm package using dnf.

apt update

Command to update the APT database of available packages.

apt upgrade

Command that installs all available package updates.

apt dist-upgrade

Command to update the full distribution.

apt autoremove

Command used to remove unused packages.

apt install

Command to install a package on systems using APT.

apt search

Command to search the repository for packages.

apt show

Command to show detailed package information.

ps command

The command used to obtain information about processes currently running on the system.

top command

A command providing real-time information about the most active processes; it can renice or kill processes.

grep command

Short for "global regular expression print," it searches files for patterns using regular expression metacharacters.

boot.log

Log containing services started via SysV scripts and messages recorded during startup.

cups/ log

Log files related to printing.

GDM logs

Log files related to gnome.

messages / syslog

Logs containing general messages.

secure logs

Logs containing security-related information.

Xorg.0.log

Information on the most recent startup of the X Window System.

kernel ring buffer

A record of recent messages generated by the Linux kernel; at bootup, it contains messages from drivers and major kernel subsystems.

dmesg command

A command that displays hardware-related messages generated by the Linux kernel from the ring buffer.

iwlist

A command that identifies nearby Wi-Fi networks.

iwconfig

A command-line utility for viewing and setting wireless interface parameters.

ifconfig

A TCP/IP configuration and management utility used with UNIX and Linux systems.

route command

A command-line tool that shows a host's routing table.

/etc/resolver.conf

The dns host file.

ip address show

A command that serves the same purpose as ifconfig.

ip link show

Shows the interfaces along with details on them.

ip link set

Command to change the state or configuration of a link.

whoami

Displays the current username.

who command

Displays the users who are currently logged in to the Linux system.

JCPU

An entry of the w command identifying the total amount of CPU time associated with the session.

PCPU

An entry of the w command identifying the total amount of CPU time associated with the current process running in the session.

adduser / useradd

Commands used to add a user to the system; useradd often uses flags like $s$ for shell and $m$ for home directory creation.

passwd -S username

Displays the status of the user account.

chage -l username

Displays the status of the user account regarding password aging.

sticky bit

A directory permission which specifies that only the owner of a file in that directory can rename, move, or delete it.

Cloud Computing

The on-demand availability of computer system resources, like data storage and computing power, without direct active management by the user.

--help

A valid option for a typical command to get its built-in usage information.

1>

The notation used to redirect the standard output of a command to a file.

Read statement

Used in a shell script to get input from the terminal.

/dev/hda2

Identifies the second partition on the first hard disk on the first IDE controller.

/dev/hdb3

Identifies the third partition on the second hard disk on the first IDE controller.

man -k copy

A command line used to search help files that mention the word 'copy'.

tail -c

An option used with tail to print the last X bytes of a file to the screen.

-gt

The correct statement for 'greater than' comparison in a Linux shell script, e.g., if [$x -gt $y].

File Truncation

The reason a file (like data.txt) becomes empty if you execute a command like sort data.txt > data.txt.

host command

A command used to resolve a DNS name to an IP address.

ls -d

A command used to show information about a directory or a symbolic link specifically.

/etc/shadow

The file modified to set the maximum number of days before a password must be changed.

/tmp

The directory for temporary files that can be safely deleted during a reboot.

/boot

The directory containing all installed kernels and their needed drivers.

rm -rf

A command that removes all files in the current directory and subdirectories forcefully.

/sys

A virtual or pseudo filesystem used to interface with the kernel and system as a whole, but not individual processes.

free command

Used to view memory usage on a system.

tar -c / tar -x

Flags used to create (-c) or extract (-x) tar archives.

tar -v / tar -f

Flags used for verbose output (-v) and to specify a file (-f) during tar operations.

tar -j / tar -z

Flags used for bzip2 compression (-j) or gzip compression (-z) in tar.