Misc Flashcards
How to remove everything from the current text insertion point to the end of the line
Control K
How to remove everything from the current text insertion point to the beginning of the line
Control U
Options for help
–help, -h, info, man
How to have grep ignore case …
run it with the -i option
How to have grep search directories
use the -r (recursive) option
grep -r will search through all files in a directory …
and in all subdirectories
Compare differences between two files
diff -y
What makes a file hidden
Prefacing it with .
Chmod number values for read write and execute:
4 if you want to give read permission
2 if you want to give write permission
1 if you want to give execute permission
How to kill a job using job number
precede a job number with a percent sign, %
How to exclude numbers from metacharacter bracket range
insert an exclamation mark, ! , or a caret, ^ immediately after the opening bracket the shell will match anysingle character that is NOT included within the brackets
How to comment in a shell script
, except with #! the hashbang line
Value of HOME
The absolute pathname of your home directory
Value of PATH
The list of directories the shell will search when looking for the executable file associated with a command you entered at the command line
Value of SHELL
The absolute pathname of your default shell
Value of PS1
Your command line prompt - what you see after entering each command
Value of PS2
The secondary prompt - what you see if you continue a command to a second line
How to run a previous command with an event number
you can run it again by using an exclamation mark, ! …
followed by the event number
$ !517
How to use command substitution
$(COMMAND)
Where COMMAND is any valid Unix command
Test if two numbers are equal
-eq
Test if two numbers aren’t equal
-ne
Test if the first number is greater than or equal to the second
-ge
Test if the first number is greater than the second
-gt
Test if the first number is less than or equal to the second
-le
Test if the first number is less than the second
-lt
Test if two strings are the same
=
Test if two strings are different
!=
Test if both expressions are true
-a
Test if either expression is true
-o
Test if one number is greater than another within a script
test $number1 -gt $number2
or
[ $number1 -gt $number2 ]
Read a value from a user’s keyboard
read value
