Linux Academy - Linux Essentials Flashcards
(339 cards)
1
Q
What does GNU stand for?
A
Gnu is Not Unix
2
Q
What does GPL stand for?
A
General Public License
3
Q
“What does ““Copy-left”” refer to?”
A
Communicates the idea of the guaranteed right to copy software.
4
Q
What does FSF stand for?
A
Free Software Foundation
5
Q
When was the FSF founded?
A
1985
6
Q
Who founded the FSF?
A
Richard Stallman
7
Q
”"”Free as in speech, not free as in beer”” refers to what?”
A
Free does not necessarily refer to price
8
Q
What four software freedoms define the FSF?
A
1.) Freedom to usethe software for any purpose2.) Freedom to examine the source code and modify it as you see fit.3.) Freedom to redistribute the software4.) Freedom to redistribute your modified software
9
Q
What are the two major version of the GNU GPL in use today?
A
GPLv2 and GPLv3
10
Q
Give an example of something that uses the GPLv2.
A
The Linux kernel
11
Q
What is the major difference of the GPLv3 too the GPLv2?
A
The GPLv3 stop restrictive hardware.
12
Q
Which GPL’s does the FSF support?
A
V2 and v3 only.
13
Q
What is the LGPL?
A
Lesser General Public License. Used for libraries (collections of code).
14
Q
What is the GNU FDL?
A
GNU Free Documentation License. Used to license open source documentation.
15
Q
What is the OSI?
A
The Open Source Initiative.
16
Q
Who founded the OSI?
A
Bruce Perens and Eric Raymond
17
Q
When was the OSI founded?
A
1998
18
Q
What was the primary concern that caused the OSI to be founded?
A
The FSF seemed threatening to some businesses. The OSI is less dogmatic and more friendly to businesses.
19
Q
What does the OSI do?
A
Promotes software in the business world.
20
Q
What is open source?
A
A development method for software that harnesses the power of the distributed peer review and transparency processs. The promise of open source is better quality, higher reliability, more flexibility and lower cost and an end to proprietary lock in.
21
Q
What are some of the licenses that fall under the OSI?
A
GPL and LPHP, Apache, MIT, BSD, FreeBSD, MPL2 (Mozilla), NCSA, OpenLDAP, Public Domain, PHP License
22
Q
“In reference to the GPL, complete the following statement: ““The derived work must also be distributed under the..”””
A
GPL
23
Q
What is the single largest difference between the FSF and OSI?
A
Under certain licenses (MIT and Apache) the OSI does not object to companies have closed source software. Opposite to this, under FSF licensing you must distribute your source code. Free does not necessarily mean price.
24
Q
What does FOSS stand for?
A
Free and Open Source Software
25
What are the 3 characteristics of FOSS?
1.) Computer software that can be classified as both free software and open source software. That is, anyone with this license is free to use, copy, study and modify the software in any way.2.) The source code is shared, encouraging people to voluntarily improve the design of the software.3.) This is in contrast to propietary software, where software is under copyright and the source is usually hidden.
26
What are the core OSI principles?
1.) Permission to derice works: License permits others to modify distributed software under the same license as the orginal.2.) Respect for source code integrity: The license may restrict redistribution of modified source but only if the patch files may be distributed along with original source code.3.) No discrimination against persons or race4.) No discrimination against fields of endeavor5.) Automatic license distribution: License must apply to anyone who receives the program with out needing a seperate agreement.6.) Lack of product specificity: The license must not require that the program be used or distributed as past of a larger program.7.) Lack of restrictions on other software: Can't restrict other software bundled with software8.) Technologically neutral.
27
Define the Free in FOSS
The code must always be available.
28
True or false: Under the GPL and FSF that uses a code under the GPL has to then release any new code under the GPL.
True
29
What are the major open source licenses?
BSDMIT (X11 License)ApacheArtisticNetscape Public License (NPL)Mozilla Public License (MPL)General Public License (GPL)Lesser General Public License (LGPL)
30
Give two examples of software that doesn't qualify as open source that might be on a Linux system.
NVidiaFlash
31
Give four examples of ways an open source business model can profit.
Dual licensingMultiple productsBounties: users pay for desired featuresDonations
32
Give four examples of where Linux is found.
Server roomsCloud computingEmedded (Android, TiVo, GPS, etc)Airport signageMars roverAnd so much more!
33
What is a widget set?
A library which usually handles GUI features such as menus and icons.
34
What are the two most common widget sets?
GTK+ and QT
35
What is the KDE Desktop Environment
K Desktop Enbironment.Default DE in Mandriva and Suse Linux.Built using the QT Widget set.
36
What is the GNOME Desktop Environment?
Default DE for RedHat, CentOS, Fedora, Debian and more.Built on top of the Gimp Tool Kit (GTK+) widget set.
37
What is the XFCE Desktop Environment?
Originally modelled as a commercial DE.Provides more customization than GNOME or KDE.Built using GTK+.Originally known as CDE.Aims to use little resources.Can be found in Xubuntu and Debian.
38
What does BASH stand for and what does it do.
Born Again Shell.BASH is a shell, that offers a command line.
39
Define Virtualization.
The creation of a virtual operating system through a virtualization software that is known as the hypervisor.
40
Give four examples of virtualization software.
Virtual box (open source)VMWareKVM/QEMUXEN
41
What is a shell?
A command line interperter.
42
How would you long list out the contents of a directory and show hidden files?
ls -al
43
What does the pwd command do and what does it stand for?
Prints the working directory, literally stands for print working directory.
44
Where are commands in the Linux file system run from?
Commands in Linux are not truly run from the current working directory. They are run from path environment variables.
45
True or false: Command and directories are case sensitive.
True.
46
What is the command to print the environmental variables on the current user?
env
47
What does the top command do?
Lists processes and applications.
48
What does the which command do?
Lists where an application lives.
49
What is a command to print out the current logged in user?
whoami
50
What does the netstat command do?
Displays current status of the network.
51
What does the ifconfig command do?
Show network interface cards (NIC) configurations that are set.
52
What does the ip addr command do?
Show network interface cards (nic), configurations that are set.On newer linux distros, similar to ifconfig.
53
What does the uname command do?
Displays operating system information.
54
What does the .bash_history file do and where is it?
Stores command line history and it is a hidden file located in the users home directory.
55
Using the command line, what does tab do?
Automatic command completion and or suggestion.
56
Using the cd command how would you go up one directory?
cd..
57
What does the cd command do?
Changes directory.
58
What run level is the GUI environment?
Run level 5.
59
Where are command aliases stored?
etc/bashrc
60
What bash profile file would you edit for all users?
etc/profile.c
61
What is stored in the .bash_logout file?
Logout prefernces
62
What user specific bash profile file stores user preferences?
.bash_profile or .profile depending on distro
63
What is .bashrc?
Non login shell that stores user specifications and aliases
64
What are environmental variables?
Set of variables any program can acces
65
What symbol and or key on the keyboard switches to the home directory and represents the $HOME environmental variable?
"""~"" - The tilde"
66
How would you echo out the $HOME variable
echo $HOME
67
What is the default value of the BASH environmental variable?
/bin/bash
68
What is the default value of the SHELL environmental variable?
/bin/bash
69
What is the default value of the ENV environmental variable?
Distro specific. In CentOS it would be /etc/bash.bashrc
70
What does the EUID environmental variable represent?
The user id of the current user.
71
What does the DISPLAY environmental variable represent?
The local video card monitor
72
What is the PATH environmental variable?
Distro dependent, stores list of directories to be searched when running a command from the shell prompt
73
What does the LOGNAME environmental variable represent?
The username of the current user.
74
What does the MANP environmental variable represent?
Distro dependent, documentation/manual pages (man pages)
75
To what environmental variable would you add custom command to so that the Linux operating system can find them?
PATH, PATH=$PATH:/some/directory/here. Don't forget the export command when doing this.
76
"What would the command ""export PATH"" do?"
Now all other users will have access to whatever program is in /some/directory/hereIn order to make this persistent across a reboot you have to edit .bash_profile
77
"True or false: ""-"" and ""_"" can be used in variable names, do not use as first character though."
True
78
What file would you edit to share a custom command (with the PATH variable) with all users?
/etc/profile
79
What is the PATH variable?
List of directories to search when running a command
80
Define globbing
global command - The process of expanding a non specific file name containing a wildcard character into a set of specific file names that exist on storage, server or network
81
"Where does the term ""globbing"" come from?"
Comes from the etc glob program in Unix, that would expand on wildcard patterns. Later on this got built in to the shell.
82
Define wildcard.
"Placeholder that represents a character, ""*"", ""?"""
83
How would you list all files in a directory using a wildcard?
*.* or just *.txt for text files, etc..
84
How would you list all txt files that only had 1 character as their name?
ls ?.txt
85
"True or false: You can use multiple ""?""; for instance ""???"" ""?????"" "
True
86
"How would you list all files starting with an ""F"" that have the txt extension?"
ls [F]*.txt
87
"How would you list all files that begin with ""f"" and have either ""i"", ""g"" or ""h"" as the second letter?"
ls f[igh]
88
Explain double quoting.
Double quote - substitutes the value of variables and commands.
89
Explain single quoting
Single quote - This preserves the literal meaning of each character of a given string, This will turn off the special meanings of all characters.
90
"Explain why you would use the backslash, ""\"""
Backslash - this takes away, or removes the special meaning from a single character, can be used as an escape character.
91
"What is the back tick key used for, ""`""?"
"""`"" - The back tick key, used for command substitution"
92
"Explain the difference between command parameters prefixed with a ""-"" and command parameters without a leading ""-"""
"Parameters with a dash ""-"" are called optionsParameters with no leading dash are called arguments"
93
Explain the relationship between the command, the options and the arguments.
command - what to dooptions - how to do itarguments - what to do with it
94
The Linux MAN pages, what does MAN stand for?
The Manual Page System, or in short man pages.
95
List the manual sections from the MAN pages.
1.) Executable programs and shell commands2.) System calls provided by the kernel3.) Library calls provided by the program libraries4.) Device file (usually stored in /dev)5.) File formats6.) Games7.) Miscellaneous (macro packages, conventions, and so on)8.) System administration commands (programs run mostly or exclusively by root)9.) Kernel routines
96
Give three examples of how to use the man command in order to find help with a specific command.
man man cp - copyman cal - calenderman passwd - passwordman 5 passwd - pull up specific file format information about passwd. Note the 5, as in section 5 of the MAN pages, or the file format section
97
What does the whatis command do?
whatis - returns 1 line from each section for input keyword
98
Give an example of using the whatis command.
whatis passwd - will return 3 lines of information about the passwd command
99
What does the apropos command do?
apropos - command for a more thorough search through the MAN pages, returns everything that keyword is in
100
What does the man -k man do?
"""man -k man"" will do the exact same thing as ""apropos man"". The -k stands for keyword. This is a much more efficient way of searching."
101
How are the man pages organized?
"MAN pages are organized as follows:- Name - - Synopsis - How command is actually used and lists optional parameters that appear in square brackets. Could follow up optional commans with ""..."" (three periods). Which denotes an optional set of repeated elements such as multiple file names if a command takes 1 or more files names as options. Some commands provide multiple synopsis lines indicating that certain options are contingent on other options fist. Basically this is just a fancy way of saying multiple options and files can be used at the same time. If you see an option underlined, it means you must use it. Such as in the mv (move) command where you must specify the source and destinations file or directory.- Description - Summary of command, file or other action does- Options - Commonly referred to as flags. Expands on Synopsis section above. Explains what each of the options/flags will do.- Files - Will list files associated with the man pages subject. Configuration files for servers or other programs that could possibly be related to config files- See Also - Provides pointers for related material within the MAN system- Bugs -- History -- Author -"
102
True or false: Commands, filenames and command flags/options are case sensitive in Linux?
True
103
What text viewer does the MAN system use?
less
104
"True or false: Editing the ""PATH="" in the .bash_profile or .profile would be at the specific user level."
True
105
"In order to print out the dollar amount with the correct formatting what character would you add to the following command?echo ""The cheeseburger is going to cost you $5.00"""
"The ""\"" escape character. echo ""The cheeseburger is going to cost you \$5.00"""
106
What command is used to get the word count of a file?
wc
107
What is the ', or the back-tick, used for?
"Command substitution. Example: echo ""Did you know that there are 'wc -w
108
"True or false: You can use ""\"" to escape and type command on multiple lines"
True. Example:
ls \
-all
109
What are the two main features that seperate info pages from MAN pages?
Info Pages- Similar to MAN but the goal is to support functions in which MAN can not- Most notable are hyperlinks, MAN does not have hyperlinks- You can use Info Pages to read MAN pages
110
What are the info pages key commands?
Info Pages key commands:? - Displays help informationN - Moves to the next node in a linked series or levelP - Moves back in a series or levelU - Moves up one level in the node hierarchyArrow keys - moves the cursor around the screen to select linesPage up, Page down - Scroll up and down within single nodeEnter - Moves to a new node once you have selected itL - Displays the last info page you readT - Displays the top page for a topicQ - Exits from the info page system
111
Why do some programmers not support info pages?
Because they are resistant or slow to adopt new systems even though MAN has been around for decades and does not support new features.
112
Besides man pages, info pages and the internet what is another way to get help in Linux?
"Many Linux distro's ship documentation as a seperate package from the actual package that is the program. These are typical named by ""-doc"" or ""-documentation"" in the package name.
Readme text files for unzipped source files are usually found in:
- /usr/doc/packagename
- /usr/share/doc/packagename
- /usr/share/doc/packages/packagename
"
113
Where are configuration files typically located?
In the /etc directory
114
In an RPM based distro, how would you use the RPM tool to locate documentation?
Example:rpm -ql packagename | grep docrpm -ql yum | grep README
115
How would you find specific keyword(s) within a directory?
"find /usr/share/doc -name ""*passwd*"""
116
True or false: the locate command is faster than the find command.
True.
The locate command is faster than find but not directory specific, searches database of programs that Linux maintains:
locate passwd
117
What does the updatedb command do?
Creates and or updates database of file names used by the locate command.
118
What does the whereis command do?
Searches standard directories where programs might be installed.Example:whereis passwd
119
True or false: The less utility can read most file formats.
True
120
Whe .1 - .9 file formats can be read by what programs?
man, info, less
121
The .gz or .bz2 file formats can be read by what programs?
gunzip, bunzip, less
122
The .txt file format can be read by what programs?
less and any text edit such as vi and vim
123
The .html and .htm file formats would be read with what program?
web browser
124
The .odt file format would be read with what program?
LibreOffice, OpenOffce, any word processor
125
The .pdf file format would be read with what program?
xpdf, Adobe Reader
126
The .tif, .png and .jpg file formats would be read with what program?
Gimp
127
What is the FHS?
File system Hierarchy Standard.
- The Linux file system uses a hierarchy structure to organize data
- Linux systems have a standard in which at the root directory has several of the same sub directories in a certain order or fashion
- Root folder is the top level directory
128
Give an example of the FHS on the command line.
"[user@computer1 /]$ - the ""/"" means we are at the top level directory "
129
Considering the FHS, under the root directory what are some common directories?
bin - contains binaries, or executable files, necessary to run the Linux file systemboot - contains boot loader files to boot Linux systemdev - contains special files used to represent various hardware devices which could be installed on systemetc - contains text based configuration files
130
Under /etc what are some common configuration directories?
/etc/aliases - Contains a table used to redirect all to local users/etc/exports - Configured file systems to be exported to remove NFS clients/etc/fstab - Lists the partitions and file systems that will be automatically mounted when we boot our Linux system/etc/ftpusers - Controls users access to FTP service running on a Linux system/etc/group - Contains local group definitions/etc/grub.conf - Contains configuration parameters for the init process/etc/hosts - Contains a list of hostname to IP address mappings for resolving certain hostnames, ie: localhost too 127.0.0.1/etc/inittab - Contains configuration parameters for the init process/etc/init.d - Sub directory that contains startup scripts and services/etc/rc.d/init.d - Red Hat or CentOS based systems startup scripts/etc/passwd - Linux systems users accounts file/etc/shadow - Contains encrypted passwords for user accounts/etc/resolv.conf - This is where we specify what DNS server and domain suffix that our system is going to use/etc/X11 - X windows configuration files
131
What does the home directory contain?
The home directories of all users on the system
132
What does the /lib directory contain?
Contains code libraries for programs to use that live with the bin or sbin folders
133
What does the /media directory contain?
Used by some distros to mount external devices such as external hard drives and USB thumb drives
134
What does the /mnt directory contain?
Used by some distros to mount external devices such as CD drives, DVD drives, USB drives and so on
135
What does the /opt directory contain?
Contains files for some programs that you can install on your own manually
136
What is the /proc directory used for?
This folder is a psuedo file system that is dynamically created whenever it is accessed. Used to access processes and other system information from the Linux kernel. Within the proc directory there are subdirectories. They are named by numbers. These numbers correspond to a process id number.
137
What does the /sbin directory contain?
Contains important system management and administration files. Could include utilities such as FDisk, FSCH, ifconfig, init, makefs, shutdown and halt.
138
What does the /srv directory contain?
Contains sub directories where services running on our system, such as HTTPD (Apache web server), actually save there files.
139
What does the /sys folder contain?
Contains information about the hardware within our system
140
What does the /tmp folder contain?
Contains temporary files that are created by the file system
141
What does the usr folder contain?
Contains application files. Most application files are stored here.
142
What are some common /usr sub directories?
/usr/bin - Where most executable programs actually live/usr/etc - /usr/games - /usr/include - /usr/lib - Library files for applications that reside in the /usr/bin directory/usr/lib64 - 64 bit library files for applications in the bin directory/usr/libexec - /usr/local - Locally installed software that we have created ourself/usr/sbin - Similar to bin but system administration programs/usr/share - Documentation and MAN page files/usr/src - /usr/tmp -
143
What is the /var directory used for?
Contains Linux variable data including Linux log files
144
What is the Linux file system responsible for in regaurds to organizing data?
The Linux disk file system is responsible for the reliability of storing data on the harddrive and then organizing this data so that is easily accessible at a later date.
145
What does ext2 stand for?
Second Extended File System 2 (ext2)
146
When was ext2 introduced?
1992
147
How does ext2 store data?
Stores data in a hierarchical manner, similar to most other distros.
148
In ext2 what is the maximum file size?
2 terabytes
149
How large can an ext2 volume be?
4 terabytes
150
In ext2 how long can a filename be?
255 characters (256 bytes)
151
True or false: ext2 supports users, groups and permissions
True
152
Does ext2 support compression
Yes
153
What is the one major disadvantage of ext2?
"Must check entire file system if file system goes down ""un-cleanly"" as in a system crash or power outage. This can take an incredibly long time."
154
True or false: ext3 is an updated file system of ext2
True
155
What does ext3 stand for?
Stands for Third Extended File System 3 (ext3)
156
Can you upgrade ext2 too ext3?
Yes
157
Can you downgrade ext3 too ext2?
Yes
158
True or false: ext3 supports journaling
True
159
Explain the concept of journaling
"System does not have to check entire system if file system goes down ""un-cleanly"" as in a system crash or power outage.- Records transactions to what is called a journal and marks it as incomplete. After this disk transaction is complete the ext3 file system marks that transaction as complete within this journal.- Replays journal if system did no go down cleanly upon system boot up and completes all transactions not yet completed. - Much faster system data verification because it does not need to check entire file system."
160
True or false: The Reiser file system is an alternative to ext3
True
161
Does Reiser implement journaling
Yes
162
True or false: Reiser has a dramatically similar file system to ext3.
False.Dramatically different file structure to support larger file sizes
163
What is the maximum file size of Reiser?
8 terabytes
164
What is the maximum volume size of Reiser?
16 terabytes
165
True or false: The Reiser file system structure does not allow for faster operation than ext2 or ext3
False.File system structure allows faster operation than ext2 or ext3
166
When was ext4 released?
2008
167
What does ext4 stand for?
Forth Extended File System (ext4)
168
What is the maximum file size in ext4?
16 terabytes
169
What is the maximum volume size in ext4?
1 exobyte
170
What is the maximum amount of files you can have in ext4?
4 billion
171
How does ext4 verify the integrity of the journal file?
Employs the use of checksums
172
What is a checksum?
A short and not very good explanation: A number which is calculated by a mathematical operation and used to verify file integrity. Checksums are used in the etx4 file system to verify the integrity of the journal file.
173
What does the pwd command do?
Prints the working directory, the working directory simply means the directory you are currently in.
174
Using the cd command, how would you go up one directory?
"The shortest way to do this would be ""cd.."""
175
Using the cd command, how would you go up two directory levels?
cd ../..
176
What does the ls command do?
Lists contents of a directory
177
What is an absolute path?
The entire directory address, for instance /home/user1 is the absolute path for user1 home directory
178
Using ls, how would you list the contents of a specific directory?
ls /path/to/directory (absolute path)
179
How would you display the long list of a folder?
ls -l
180
How would you display the long list of a folder, including hidden files?
ls -al
181
How would you list a folder and it's subdirectories?
ls -R
182
What would be a way to pup the results of ls -R in to the more command in order to page through the results?
ls -R | more
183
"What does the ""."" as the first character of a file or folder mean?"
That that file or folder is hidden
184
True or false: If you use touch on an existing file it will update that files timestamp to the latest date and time.
True
185
The -c argument or flag in the touch command would do what?
Don't create a new filename if the filename does not exist and do not notify of this. Good for simply updating a timestamp without creating a new file.
186
How would you update the time smap of file.txt to February 1 2016?
"touch -d ""February 1 2016"" file.txt
This will change the timestamp of file.txt to ""Feb 1 00:00""
"
187
True or false: Touch can be used to make directories
False. Use the mkdir command for this.
188
What are some common arguments of the cp command?
cp -f - Force file overwrite without prompt.cp -i - Interactive flag, prompt before overwrite.cp -p - Preserve mode, keep ownership and timestamps.cp -R, r - Recursive option, copy sub directories.cp -a - Archive, copies recursively and preserves ownership of folders being copied. Can be used to copy symbolic links!cp -u - Copy original file only if source file is newer than destination file or if destination file does not exist.
189
What is the mv command used for?
To move files
190
How would you rename a file using the mv command?
mv file1.txt newname.txt
191
Using the cp command how would you copy a file?
cp file.txt file1.txt
192
Using the rm command how would you delete a file?
rm newname.txt
193
Using the mkdir command, how would you create a directory?
mkdir dir3
194
Using the rmdir command, how would you delete a directory?
rmdir dirtest1
195
What are some escape characters?
Special escape characters:\a - alert(bell)\b - backspace\e - an escape character\f - form feed\n - new line\r - carriage return\t - horizontal tab\v - vertical tab\\ - backslash\' single quote\nnn the eight-bit character whose value is the octal value nnn (1 to 3 digits)\xHH - the eight-bit character whose value is the hexadecimal value HH\cx - control x character
196
What is the tar utility?
"- A Linux utility that archives things. It does not compress or compact files. It just sticks all your files together in to one file.- Originally used to create tape backups. Used it to archive data on to tape backup drives. Tar actually stands for ""Tape Archive""."
197
What would tar -cf do?
Create a file
198
What would tar -xf do?
Extract a file
199
What are the 3 primary compression utilities on the Linux file system?
Gzip- gzip- gunzipBzip2- bzip2- bunzipZip- zip- unzip
200
True or false: Zip is the only command that both archives and compresses in one pass
True
201
True or false: Tar is used together with a separate compression utility to both archive and compress.
True
202
Using zip, what must you do to ensure it recusively goes through a folder and its contents and zips everything up?
zip -r foldernamezip.zip folderThe -r argument is important here.
203
Using 2 steps, how would you use tar and gzip together to both archive and compress a folder?
tar -cf folder1.tar folder1gzip folder1.tar
204
Using 1 step how would you use tar and gzip together to both archive and compress a folder?
tar -zcf folder1.tar folder1
205
What does the cat command do?
Displays contents of a file, manipulates data by columns
206
What does less do?
Reads a file
207
What does the head command do?
Reads first 10 lines of a file
208
What does the tail command do?
Reads the last 10 lines of a file.
209
What does the find command do?
Locates files on system
210
What does the grep command do?
Searches a string in our file or output
211
What does the sort command do?
.... sort text in a file or output ....
212
Using find, how would you find only directories within the current directory?
find . -type d
213
Using find, how would you find only files within the current directory?
find . -type f
214
Using find, how would you find everything within the current directory?
find .
215
"Using find, how would you find files that had the partial string of ""derp"" in their names?"
"find . -name ""derp*"""
216
What does the -i argument do with the grep command?
Searches for both upper and lower case.
217
Using the -n flag with the grep command would do what?
Prints out line numbers with search results
218
By default how does the sort command organize data?
alphabetically
219
How would you numerically organize data with the sort command?
sort -n
220
Using the man command how would you look up information about grep?
man grep
221
Contents of file.txt:thisistext in a fileThe command cut -c2 file.txt would display what?
hse
222
Explain the cut command
Linux command cut is used for text processing. You can use this command to extract portion of text from a file by selecting columns.
223
Text file test.txtthis is a testthis is a linethis is more textUsing the cut command how would you but information from the third character of each line to the end of the line
cut -c3- test.txt-c3 specifies the third column, the - specifies a range, but no end of the range was specified, so end of line is used by default
224
The -c argument in the cut command would denote what?
column
225
"Using grep, cut and the delimeter of "":"" how would you display users who had the login shell of /bin/bash?"
"grep ""/bin/bash"" /etc/passwd | cut -d':' -f1,6The delimeter "":"" specifies what seperates out field. And if you looked in /etc/passwd said ""fields"" would be username(1) and home directory(2)."
226
Using the cut command was the -d argument denote?
delimeter, used to define what seperates fields. Allows for organizing of data more easily.
227
What is a delimiter?
A delimiter is a sequence of one or more characters used to specify the boundary between separate, independent regions in plain text or other data streams. An example of a delimiter is the comma character, which acts as a field delimiter in a sequence of comma-separated values.
228
"This command:cut -d"" "" -f2 file2.txtWould do what?"
Delimit (space) and create a field off of space. This will basically break text file in to words and return the second word from each line.
229
Explain what a file descriptor is.
In Unix and related computer operating systems (Linux), a file descriptor (FD, less frequently fildes) is an abstract indicator (handle) used to access a file or other input/output resource, such as a pipe or network socket. File descriptors form part of the POSIX application programming interface.
230
What the standard BASH file descriptors?
stdin - This means we have standard input 0stdout - This means we have standard output1stderr - This stands for standard error 2
231
True of false: Not all commands use the three standard file descriptors of stdin, stdout and stderr but most of them do.
True
232
"Using the find and grep commands how would you find all files that include ""abc"" in the name?"
find . type f | grep abc
233
"Command:cut -d"" "" -f3 file2.txt | cut c2What would this do?"
Return 3rd word from each line and then return the second letter from each of those words.
234
Using the tail command and command redirection, how would we output the last ten lines of the file /var/log/messages in to logtemp.txt?
tail /var/log/messages > logtemp.txt
235
"What does "">>"" in command redirection?"
Allows for redirection that will append.
236
Give an example of command redirection that appends running processes in to a file.
ps >> runningprocesses
237
"Using the word ""command"" as an abstract placeholder, how would you use command redirection to handle both succesful completion of a command and an error at the same time with file descriptors."
command 1> stdout_file 2> stderr_file
238
How would you send the text string of the file /var/log/messages to the tail command using command redirection?
tail < /var/log/messages
239
How would you send a file called words.txt to the sort command?
sort < words.txt
240
What are regular expressions?
Basically, a regular expression is a pattern describing a certain amount of text
241
What does regex stand for?
Regular expressions.
242
What does the regex expression * do?
Matches any characterfile*
243
What does the regex expression . do?
Any single character
244
What does the regex expression ? do?
Matches zero of one of the proceeding characters.f?le
245
What does the regex expression ^ do?
Matches expression if it appears at the beginning ^file
246
What does the regex expression $ do?
Matches expression if it appears at the endfile$
247
What does the regex expression [nnn] do?
Matches any character between the braces[abc]
248
What does the regex expression [^nnn] do?
Matches any expression that doesnt contain any of the characters specified, [^abc] will not match a, b or c
249
What does the regex expression [n-n] do?
Matches any single character
250
Command:grep cc$ abc.txtWhat would this regex search do?
"Return lines and or characters ending in ""cc"" from abc.txt."
251
Command:grep ^ab abc.txtWhat would this regex search command do?
"Returns lines and or characters starting in ""ab""."
252
Command:grep .cc abc.txtWhat would this regex search command do?
"Returns lines and or characters that have anything followed by ""cc"". For instance, ""acc"" and ""bcc""."
253
Command:grep ^.b abx.txtWhat would this regex search command do?
"Returns lines and or characters that start with anything and are followd by a ""b"". For instance, ""ab"" and ""abc""."
254
Command:grep ^...$ abc.txtWhat would this regex command do?
Returns lines and or characters that starts with 3 characters of anything and is only 3 characters long.
255
When you first open the vi text editor, what mode are you in?
command mode
256
In vi how do you get to insert mode?
i, INSERT, s, o and or a
257
What does hitting the insert key twice do in vi?
Allow the over riding of text
258
True or false: When in insert mode, in vi, you can perform file operations.
False
259
When in vi how do you get back to command mode?
Press the escape key
260
In vi how do you enter a command?
"Press "":"""
261
What does the w command do in vi?
writes a file (save)
262
In vi how would you save an existing file in to a new name?
vi newfilename
263
In vi what does the wq command do?
writes and quits
264
What are some common vi commands?
w - write (save file)w newfilename - save file with a new nameexit - guess what this does, go ahead just guess..............wq - write and quitq - quit, does not savew! - overwrite current filee! - forget changes sense last write dw - delete word in front of cursor including the spacede - delete word in front of cursor without deleting the space d - delete entire line, can use p to move line elsewherep - paste/ - findn - next, used with / for tabbing through search results
265
What is the shebang?
#! Special characters that start a bash script
266
What would exit status 0 be if a basch script executed correctly?
Exit 0
267
What would exit status 1 be if a basch script executed incorrectly?
Exit 1
268
True or False: if/then/else is a branching structure.
True
269
Name the three looping structures
while loopuntil loopfor loop
270
What do while loops do?
```
Execute over and over until a specified condition is no longer trueExample:
while condition
do
script command
done
```
271
What do until loops do?
```
Execute over and over until a specified condition is no longer trueExample:
until condition
do
script command
done
```
272
What does the for loop do?
"Will loop a specified number of times.Example:
for i in 'seq 15'
do
echo ""the current number in the sequence is $1.'
done
exit 0
"
273
"Example script:
#!/bin/bash
#list contents of directory and write output to a file
location=$1
filename=$2
ls $location > $filename
echo ""Script is complete and has indexed the $location""
echo ""######""
echo ""Displaying contents of our $filename""
echo ""######""
cat $filename
How would you execute and pass the required data to this script assuming the script is called ""findlist.sh""?"
./findlist.sh /tmp name_of_file - This will list directory contents of /tmp
274
When it comes to bash scripts what does -z do?
"It is a comparison operator used to see if a variable exists.Example:
#!/bin/bash
#list contents of directory and write output to a file
location=$1
filename=$2
if [ -z ""$location"" ] then
echo ""Please provide location argument""
exit 0
fi
if [ -z ""$filename"" ] then
echo ""Please provide filename argument""
exit 0
fi
ls $location > $filename
echo ""Script is complete and has indexed the $location""
echo ""######""
echo ""Displaying contents of our $filename""
echo ""######""
cat $filename
"
275
Explain the steps in the idea of distributed life cycle management.
- Design- Develop- Deploy- Manage- Retire
276
What is the life cycle and release cycle of Redhat Enterprise Linux (RHEL)
life cycle management: 10 yearsrelease cycle management: 3-4 yearsThis means every 10 years the oldest version gets retired, and every 3-4 years a new version comes along
277
What is the life cycle management and release cycle management of Fedora?
life cycle management: 1 yearrelease cycle management: 6 months
278
What is the life cycle management and release cycle management of Suse Linux Enterprise Linux (SLES)?
life cycle management: 7 yearsrelease cycle management: 3-4 years
279
What is the life cycle management and release cycle management of OpenSUSE?
life cycle management: 18 monthsrelease cycle management: 8 months
280
What is the life cycle management and release cycle management of Ubuntu(LTS)?
life cycle management: 5 yearsrelease cycle management: 2 months
281
What are some key facts about the Linux kernel?
- The Linux kernel is a unix like operating system- Linux was developed and created by Linus Torvalds- The kernel is the core of any Linux installation- The kernel is responsible for managing every other piece of software on a running Linux computer- Kernel imposes order by using hierarchy- When the system boots, typically one process called the init process starts up the /sbin/init that in term manages child processes
282
What are some key facts about processes?
- Every process has an associated process id (PID)Example:init is usually process number 1- Every parent process has a parent id (PPID)- Can identify these PIDs and PPIDs with tools like ps
283
What does the ps command do?
Report a snapshot of the current processes
284
What command and argument for said command, would you use to list the processes and child processes for a specific user bob?
ps -u bob --forest
285
Using the ps and grep commands how would you determine if bob was using the program nano?
ps aux | grep bob | grep nano
286
Command:ps auxWhat does aux mean?
a = show processes for all usersu = display the process's user/ownerx = also show processes not attached to a terminal
287
What is top?
Similar to ps but in realtime and is interactive
288
What are some common hot keys of top?
h - helpk - kill a processr - change process prorietyp - sort for cpu usage (default)m - sort for memory usage
289
What does the free command do?
List system total memory status.Use the -h argument for human readable measurement.
290
What is cron?
Logs processes that run at regular intervals (cron is a linux scheduling service)
291
Where will most log files be located under?
/var/log
292
What is boot.log used for?
Log file for processes started late in the boot cycle by either startup scripts or systemd
293
True or false: When it comes to log files grep is your best friend.
True
294
"How would you use grep and a wildcard to search the entire /var/log/ directory structure for the word ""access""?"
grep access /var/log/*
295
What is a daemon?
Programs running in the background
296
"What would a ""d"" at the end of a log file signify?"
A log file for a daemon.Depending on the linux distro klog or klogd might take the place of syslog and syslogd
297
What is the kernel ring file?
The kernel ring file is sort of a log file for the kernel. However, unlike other log files this is stored in memory.
298
How would you read information from the kernel ring file?
dmesg | lessdmesg | grep consoledmesg | grep console | less
299
True or False: If a certain piece of hardware is misbehaving the kernel ring buffer is a good place to look as to why.
True
300
What are some common data locations for things like configuration files and logs?
/lib - Linked library files used by libraries in /bin and /usr/bin/usr/lib - Linked library files used by binaries in /bin and /usr/bin/etc - Configuration files for our Linux operating system/var/log - Log files for our Linux operating system
301
Did you know that most Linux distros can be configured in a wide variety of roles such as:
- Domain controller
- Database server
- DHCP server
- Web server
- Email server
- File and print server
- Packet-filtering, stateful, or even application level firewalls
- Proxy server
- Content filter server
- Router
Yes, of course I knew that, I am no buffoon you ape.
302
What do networks use in order to talk to each other?
Protocols. Protocols can be thought of as languages.
303
True or False: Computers need to speak the same langauge (protocol) in order to talk to each other.
True
304
What is the IP Protocol?
A networking protocol used on the internetWorks with other protocols such as TCP (Transmission Control Protocol)Works with the UDP (User Datagram Protocol)
305
What is the OSI reference model?
breaks down the overall communication process into specific tasks.
306
When was the OSI reference model designed?
1983
307
How many layers does the OSI reference model have?
7
308
List the different layers of the OSI reference model.
7Application6Presentation5Session4Transport3Network2Data link1Physical
309
Define all 7 layers of the OSI reference model.
7Application - Responsible for providing applications with a way that actually accesses the rest of the layers.6Presentation - Responsible for the information passing throughout all of the OSI layers is formatted correctly for the application on the destination system.5Session - Responsible for establishing and maintaining these connections between source and destination network addresses. These connections are referred to as sessions.4Transport - On the sending host this layer receives information from the upper layers. It then divides this information in to small transmittable chunks called packets. On the receiving host packets are reassembled at this layer. This layer also provides error checking mechanisms that ensures that data arrives at destination address in tact. TCP and UDP operate at this layer.3Network - Enables routing of the data. Specifies how to recognize the address of neighbouring nodes (routers for example). Basically specifies the next network point to which a packet should be forwarded towards. The Internet Protocol (IP) operates at this layer. ICMP also operates at this level.2Data link - Defines the rules and procedures for accessing the 1physical layer. Defines how hosts are identified on the network and how network mediums are accessed. Also specifies how to verify data received from 1physical layer. Information received from upper layers is organized in to datagrams.1Physical - Transmits electrical signals between the hosts. This is literally the actual network card that you would plug in to your computer.
310
Fill in the blanks:TCP and or UDP are used together with the IP to _____ data for sending over the network as well as _____ reassembling said data.
fragment, reassemble
311
True or False: TCP ensures data exchanged between two network hosts is exchanged reliably.
True.
312
What are some examples of upper layer applications that use TCP?
- Web servers- E-mail servers- FTP servers
313
What does UDP stand for?
User Datagram Protocol
314
Is UDP a connectionless profile?
Yes, UDP packets are sent unacknowledged
315
What are two examples of upper layer applications that use UDP?
Stream audioVoice over IP (VoIP)
316
What is the major difference between UDP and TCP?
TCP verifies that all information sent is received.UDP assumes that data loss and error checking are either not necessary or it is handled by some other method in the application.
317
What does ICMP stand for?
Internet Control Message Protocol
318
For what is ICMP used for?
For testing and verifying network communication between hosts
319
What utility ues ICMP to send an echo request that sends packets to a remote host; and upon the host reveiving packets will respond in turn with an ICMP echo response packet?
ping
320
What are some well known ports from 0-1023?
20 and 21 - FTP23 - Telnet25 - SMTP80 - HTTP110 - POP3137, 138, 139 - NetBIOS443 - HTTPS
321
Port numbers range from 0 up to what number for each individual address?
65535
322
Registered ports range from what too what?
1024 too 49151- Organizations can program their own network service and then apply for a registered port number to be assigned to it.
323
Dynamic ports range from 49151 too what number?
65535
324
An ip address is made up of how many groups of numbers, each of those numbers ranging from what to what?
4 numbers, seperated by a period and ranging from 0 to 255
325
At what level in the OSI model does the IP address operate at?
3network layer
326
At what level does the MAC address operate at in the OSI standard?
2datalink layer
327
True or false: Each number in the IP address is an eight-bit binary number, called an octet
True
328
Is 11000000.10101000.00000007.00000001 the correct binary representation of 192.168.1.1?
Yes! Duh.. totally knew that
329
Starting at bit 1 and going to 8, list what each bit in the 8 bit binary address means.
Bit 1 = 128Bit 2 = 64Bit 3 = 32Bit 4 = 16Bit 5 = 8Bit 6 = 4Bit 7 = 2Bit 8 = 1
330
```
with this binary address:11000000.10101000.00000007.00000001We can convert is as such:
11000000 = 128 + 64 = 192
10101000 = 128 + 32 + 8 = 168
00000007 = 1 = 1
00000001 = 1 = 1
What would the final IP address be?
```
This comes out to 192.168.1.1
331
Why can each number in an IP address not exceed 255?
Because each number is a representation of the 8 bit binary address. If you add up 128+64+32+16+8+4+2+1 it comes out to 255.
332
What would 192.168.1.0 be an address of?
A network segment. This the actual address of the host network. The last octet in an ip address can not be a 0 or 255. This is reserved for the address of the network segment itself. It identifies an entire subnet.
333
The 192.168.1.255 address would be reserved for what?
The last octet can also not be 255. This is reserved for sending the broadcast to all hosts on the segment.
334
True or False: No two hosts on the same network can have the same IP address.
True
335
Fill in the blanks:IPv4 is a _____ addressing system that only allows for a maximum of _____ possible unique IP address.
32 bit (8bit.8bit.8bit.8bit)4 billion
336
What was created to address the limitations of IPv4?
IPv6
337
Fill in the blank: IPv6 is an ____ bit IP scheme
128
338
What are IPv6 addresses composed of?
Eight, four-character hexadecimal numbers, seperated by colons.Example:FE80:0000:0000:0000:0202:B3FF:FE1E:8329
339
What is IANI and whare are they in charge of?
Internet Assigned Numbers Authority, In charge of distributing blocks of ip's.
