CLI Flashcards
CLI stands for ?
Command Line Interface.
” cat “ is used for ?
Type out or combine files.
” head “ is used for ?
Show the first few lines of a file.
” tail “ is used for ?
Show the last few lines of a file.
” man “ is used for ?
View the documentation.
The command is ?
The name of the program you are executing.
” sudo “ is used for ?
Provide user with administrative privileges.
Virtual Terminal is ?
Console sessions that use the entire display and keyboard outside of a graphical environment.
Virtual Terminal is helpful when ?
You run into problem with the graphical desktop. You can switch to VT and troubleshoot.
” shutdown -r “ is used for ?
Reboot the system.
To reboot the system, use command ?
shutdown -r
To cancel rebooting the system, use command ?
shutdown -c
The schedule shutting down the system ?
shutdown -h HH:mm “Message”
To locate program, use ?
” which “ or “ whereis “
i.e “which diff”, “whereis diff”
Display the current working directory ?
pwd
Change your current home directory ?
cd
Change to parent directory ?
cd ..
Change to previous directory ?
cd -
An absolute pathname is ?
Start with the root directory and follows the tree.
Always starts with /.
A relative pathname is ?
Start from the present working directory.
Never starts with /.
Displays a tree view of the filesystem ?
tree or tree -d
List all files, including hidden files and directories ?
ls -a
Create hard link from two files ?
ln file1 file2 (with file1 already exists)
Create soft link from two files ?
ln -s file1 file3 (with file1 already exists)
View a file that is not very long, does not provide any roll-back?
cat
Look at a file backward, starting from the last line ?
tac
A paging program, used to view larger file ?
less
Search for pattern in the forward direction with “ less “ program ?
less /{pattern}
Search for pattern in the backward direction with “ less “ program ?
less ?{pattern}
Print the last 10 lines of a file by default ?
tail
Configure to print the last 15 lines of a file ?
tail -n 15
Print the first 10 lines of a file by default ?
head
Create an empty file ?
touch fileName
Make a new directory ?
mkdir dirName
Remove an empty directory ?
rmdir dirName
Remove a file or move that file to another location ?
mv fileName
Remove a file ?
rm fileName
Remove a file interactively ?
rm -i fileName
Remove a file forcefully ?
rm -f fileName
Remove a directory forcefully ?
rm -rf dirName
When commands are executed, by defaults how many file streams are there ?
3: stdin, stdout, stderr
To set input to a file, which sign to use ?
<
$ do_something < input-file
To set output to a file, which sign to use ?
>
$ do_something > output-file
To redirect stderr to a separate file ?
Use stderr’s file descriptor number (2), the greater-than sign (>), followed by the name of the file you want to hold everything the running command writes to stderr:
($ do_something 2> error-file)
To pipe the output of one command or program into another as its input ?
|
$ command 1 | command 2 | command 3
To search for file ?
locate
$ locate zip | grep bin
Wildcard: Matches any single character ?
?
ls ba?.out
Wildcard: Matches any string of character ?
*
ls *.out.
Wildcard: Matches any character in the set of characters, for example [adf] will match any occurrence of a, d, or f ?
[set]
Wildcard: Matches any character not in the set of characters ?
[!set]
What function / command that recurses down the filesystem tree from any particular directory (or set of directories) and locates files that match specified conditions ?
find
$ find /usr -name gcc
Two most common Package Management System ?
Debian and RPM
A Package Management System has … levels ?
2 (high level and low level)
Example of high level package manager ?
dpkg (for Debian Family System)
rpm (for SUSE or Red Hat Family System)
Example of low level package manager ?
apt-get (Debian Family System)
zypper (SUSE Family System)
yum (Red Hat Family System)
What does a low level package manager do ?
+ Unpacking individual packages
+ Running scripts
+ Getting the software installed correctly
What does a high level package manager do ?
+ Works with group of packages
+ Download packages from vendors
+ Figure out dependencies
apt stands for ?
Advanced Packaging Tool
Difference between a Console and a Terminal ?
The console is a terminal. A system has got one console and potentially multiple terminals. The console is typically the primary interface for managing a computer, eg while it is still booting up. A terminal is a session which can receive and send input and output for command-line programs.
