Show:
Commands
Reg-ex
Character meanings
Editors
File Management
100
Help menus in Linux
What is -help, -man, apropos, info
100
This command will return: open re-open hole
What is “o.e”
100
OR
What is ||
100
This is a powerful text editor (the successor of ‘vi’)
What is vim
100
Remove files, directories, and their subdirectories
What is rm -r files
200
Show the last (1000 or so) commands executed from the command line on the current account.
What is history
200
How to get a literal backslash
What is \\
200
&
What causes the preceding command to execute in the background
200
root permissions for a single command.
What is sudo
200
make a new directory
What is mkdir directory
300
Used to determine the users logged on the machine.
What is who
300
make the whole expression a case insensitive
What is (?i)
300
Matches any upper-case letter from A to F
What is [A-F]
300
debug shell scripts
What is -x , set -x , set -v
300
cat filename | less less filename
What is Scroll through a content of a text file.
400
Print my login name
What is whoami
400
capture an email address for a proofpoint domain.
What is \@proofpoint\.com$
400
‘‘
What is do a command substitution inside the backquotes first.
400
The difference between PATH and path
What is colon-separated absolute paths that are stored in plain text files and latter is a file's or directory's address on a filesystem .
400
View passwords and other information concerning users who are registered to use the system.
What is /etc/passwd
500
PWD.
What is Print working directory, i.e., display the name of my current directory on the screen.
500
This will match any three digit number
What is [0-9][0-9][0-9]
500
(?:^|(?<=[\s,:#'"({[]))\d{3}([- ]?)\d{2}\1\d{4}(?=[\]\s,:;?!"')}]|\.\D|$)
What is SSN
500
In nano, to save contents without exiting... To exit nano...
What is ^O , ^X
500
3 ways to find files
What is find, which , whereis