Term
| 4.3 - What is the hierarchy in which binaries are stored? |
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Definition
"/" = Programs that are necessary in single-user mode
"/usr" = Most programs that are |
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Term
| 4.3 - What does /sbin contain? |
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Definition
Essential binaries for system administration
(Remember that some distros use symbolic links to point to /usr/sbin) |
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Term
| 4.3 - What does /bin contain? |
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Definition
Essential binaries for all users
(Remember that some distros use symbolic links to point to /usr/bin) |
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Term
| 4.3 - What does /usr/bin contain? |
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Definition
| Includes most executable files |
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Term
| 4.3 - What does /usr/sbin contain? |
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Definition
| Stores binaries for most systems administration |
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Term
| 4.3 - What does /usr/local/sbin contain? |
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Definition
| Locally installed programs not managed by the package manager |
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Term
| 4.3 - Where is potential location in a users home directory for programs? |
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Definition
/home/$USER/bin
/home/$USER/.local/bin |
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Term
| 4.3 - What is the /etc directory used for? |
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Definition
| System-wide configuration files (unlike user configurations which are stored in the user's home directory) |
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Term
| 4.3 - What is the "group" file in /etc used for? |
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Definition
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Term
| 4.3 - What is the "hostname" file in /etc used for? |
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Definition
| Contains the name of the host computer |
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Term
| 4.3 - What is the "profile" file in /etc used for? |
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Definition
| System-wide configuration for Bash |
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Term
| 4.3 - What is the "hosts" file in /etc used for? |
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Definition
| Contains a list of IP addresses and hostnames |
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Term
| 4.3 - What is the "passwd" file in /etc used for? |
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Definition
| Contains a system user database comprised of seven colon separated fields. |
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Term
| 4.3 - What is the "shadow" file in /etc used for? |
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Definition
| Contains the one-way hash values of users passwords |
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Term
| 4.3 - What does the initialization file known as "bash.bashrc" contain? |
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Definition
| System-wide .bashrc file for interactive Bash shells (remember files with the "rc" characters are initialization files) |
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Term
| 4.3 - What does the "resolv.conf" file contain? |
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Definition
| DNS configuration settings for the local resolver |
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Term
| 4.3 - What does the "sysctl.conf" file in /etc do? |
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Definition
| A configuration file for setting system variables for the kernel. |
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Term
| 4.3 - What does the ".d" mean at the end of a file? |
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Definition
| It means it is a directory. |
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Term
| 4.3 - What is the "." in ".file" mean? |
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Definition
| The "." means the file is hidden |
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Term
| 4.3 - What is the ".bash_history" used for? |
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Definition
| Stores the command line command history in the buffer. |
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Term
| 4.3 - What is the ".bash_logout" used for. |
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Definition
| This file includes commands to execute when leaving the login shell |
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Term
| 4.3 - What is the ".bashrc" file used for? |
|
Definition
| This is a Bash initialization script for non-login bash-specific shells |
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Term
| 4.3 - What is the ".profile" file used for? |
|
Definition
| Bash initialization script for login shells read by many shells (not just Bash) |
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Term
| 4.3 - What is the PID for "systemd" |
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Definition
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Term
| 4.3 - What is the "config_4.9.0-9-amd64" file used for? |
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Definition
| Config settings for the kernel such as options and modules that were compiled along with the kernel |
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Term
| 4.3 - What is the "initrd.img-4.9.0-9-amd64" file used for? |
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Definition
| Initial RAM disk image that helps in the startup process by loading a temp root file system into memory |
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Term
| 4.3 - What is the "System-map-4.9.0-9-amd64" contain? |
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Definition
| Device maps of the hard drives and this file manages memory prior to the loading of the kernel |
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Term
| 4.3 - What does the "vmlinuz-4.9.0-9-amd64" file contain? |
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Definition
| This file is the kernel proper, stores in a self-extracting, space saving, compressed format |
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Term
| 4.3 - What is in the "grub" directory? |
|
Definition
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Term
| 4.3 - What is the "/proc" directory? |
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Definition
| A pseudo file system, as it is not written to disk but stored completely in memory. It is dynamically populated every time the computer boots up and constantly reflects the current state of the system |
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Term
| 4.3 - Name three types of information we can get using "/proc" |
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Definition
1 - Running processes
2 - Kernel configuration
3 - System Hardware |
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Term
| 4.3 - What command can be used to find information about the processor? |
|
Definition
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Term
| 4.3 - What is the command to find information about strings passed to the kernel |
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Definition
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Term
| 4.3 - How can you display a list of the modules loaded into the kernel? |
|
Definition
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Term
| What is the "/proc/sys" directory used for? |
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Definition
| This directory includes kernel configuration settings in files divided into 8 subcategories. |
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Term
| 4.3 - What are the subcategories of the "/proc/sys" directory? |
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Definition
| abi, debug, dev, fs, kernel, net, user, vm (remember that each one of these subdirectories act like switches containing a "0 or 1" |
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Term
| 4.3 - What is the /dev directory contain? |
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Definition
| Device files for all connected devices, this is the interface between the devices and files using them |
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Term
| 4.3 - What are the two device categories? |
|
Definition
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Term
| 4.3 - What is a block device found in /dev? |
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Definition
| These are devices in which data is written and read in blocks which can be individually addressed |
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Term
| 4.3 - What is a character device found in /dev? |
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Definition
| These are devices in which data is written and read sequentially one character at a time |
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Term
| 4.3 - Name some examples of block devices. |
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Definition
| Hard disks, flash drives, CD/DVD drives, SDCards |
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Term
| 4.3 - Name some examples of character devices. |
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Definition
| Keyboards, text console, serial ports |
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Term
| 4.3 - What is "/dev/zero" used for? |
|
Definition
| Provides any null characters as requested |
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Term
| 4.3 - What is "/dev/null" used for? |
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Definition
| Aka "bit bucket" will discard all information sent to it. |
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Term
| 4.3 - What is "/dev/urandom" used for? |
|
Definition
| Generates pseudo-random numbers |
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Term
| 4.3 - What is the "/sys" directory used for? |
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Definition
| Contains information about hardware devices contained in "/dev" that the kernel references. This is were the "sysfs" is mounted. |
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Term
| 4.3 - What is the command to view current memory utilization? |
|
Definition
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|
Term
| 4.3 - Where does the command "free" parse its data from? |
|
Definition
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Term
| 4.3 - What does the "free -b" switch do? |
|
Definition
| Displays memory utilization in byte format |
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Term
| 4.3 - What does the "free -m" switch do? |
|
Definition
| Displays memory utilization in megabyte format |
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Term
| 4.3 - What does the "free -g" switch do? |
|
Definition
| Displays memory utilization in gigabyte format |
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Term
| 4.3 - What are the letters that can modify the behavior of "top"? |
|
Definition
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|
Term
| 4.3 - What is way to view the process hierarchy? |
|
Definition
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Term
| 4.3 - How can you view static process information about the current shell? |
|
Definition
ps
(with the -v switch, you can get verbose output)
(with the "uf" switches you can display the parent/child process relationship) |
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Term
| 4.3 - How can you display the current system load? |
|
Definition
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Term
| 4.3 - What do the last three fields in the output of the "uptime" command display? |
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Definition
1st = load average for the last minute
2nd = load average for the last 5 minutes
3rd = load average for the last 15 minutes |
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Term
| 4.3 - Where are logs sent when the kernel and processes start executing as well as the syslog daemon? |
|
Definition
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Term
| 4.3 - What is the "/var/log/auth.log" file contain? |
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Definition
| Stores information about authentication |
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Term
| What does the "var/log/kern.log" files contain? |
|
Definition
| Stores kernel information |
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Term
| 4.3 - What is the "/var/log/syslog" file contain? |
|
Definition
| Stores system information |
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Term
| 4.3 - What is the "/var/log/message" file contain? |
|
Definition
| Stores system and application data |
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Term
| 4.3 - How can you view system and applications logs, one screen at a time? |
|
Definition
| sudo /var/log/messages | less |
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|
Term
4.3 - What do
"/var/log/wtmp" and "/var/log/btmp" files contain? |
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Definition
| Non-plaintext logs that can be viewed with the "last" command |
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