Brainscape Bash

Question 1

search history forward/backward

Answer 1

CTRL-R / CTRL-S (mnemonic: Reverse history search, Search [forward])

Question 2

cancel history search

Answer 2

CTRL-G (mnemonic “Get out of here”)

Question 3

cycle through final parameter of previous commands

Answer 3

ALT-.

Question 4

cycle through completions (set manually)

Answer 4

ALT-S

Question 5

go to beginning/end of line

Answer 5

CTRL-A / CTRL-E

Question 6

go to previous / next command in history

Answer 6

CTRL-P / CTRL-N

Question 7

move forward/backward (right/left) one word

Answer 7

ALT-F / ALT-B

Question 8

toggle between beginning of line and current character position

Answer 8

CTRL-XX

Question 9

clear whole screen, similar to “clear” command

Answer 9

CTRL-L (mnemonic “cLear”)

Question 10

delete word backward / forward

Answer 10

ALT-Backspace / ALT-D

Question 11

cut word before/after cursor to clipboard

Answer 11

CTRL-W / CTRL-K (mnemonics, backward just like Vim, CTRL-K “Kill”)

Question 12

cut the whole line before the cursor to clipboard

Answer 12

CTRL-U

Question 13

paste the last thing to be cut

Answer 13

CTRL-Y

Question 14

swap current word with previous

Answer 14

ALT-T

Question 15

undo

Answer 15

CTRL-_

Question 16

revert the line to the way it was in history

Answer 16

ALT-R (mnemonic: “Revert”)

Question 17

how to make a tag on a command in history

Answer 17

just use “#tag”–anything after the tag is a comment, but will be retained in history

Question 18

how to change to the previous directory

Answer 18

cd -

Question 19

how to use the previous directory in a command

Answer 19

can be specified with “~-“ (e.g. “tar xzf ~-/moz”)

Question 20

view all history

Answer 20

history

Question 21

view last five commands of history

Answer 21

history 5

Question 22

search history for all commands with “cd” in them

Answer 22

history | grep cd

Question 23

how to do a reverse-i-search with text you’ve already entered

Answer 23

CTRL-aryr

Question 24

history for previous command name

Answer 24

!!:0

Question 25

history to execute the last “ssh” command

Answer 25

!ssh

Question 26

search history for a string not at the beginning of the command

Answer 26

!?commit?

Question 27

history to access the second word of the most recent command

Answer 27

!!:1

Question 28

history to grab everything from the second word on, of the most recent command

Answer 28

!!:1*

Question 29

history to grab everything from the beginning to the third word of the most recent command

Answer 29

!!:*2

Question 30

history to grab indices 2-3 of the most recent command

Answer 30

!!:2-3

Question 31

history for the first/last word of the most recent command

Answer 31

!!:^ / !!:$

Question 32

access history entry number 51

Answer 32

!51

Question 33

history access second-to-last most recent command

Answer 33

!-2 (-1 is most recent command, and count back from there)

Question 34

macro to add an option to the previous command (manually defined)

Answer 34

ALT-O

Question 35

meaning of single quotes

Answer 35

everything is completely literal, no escaping needed

Question 36

meaning of double quotes

Answer 36

treated like a string, except that “$” and “" are interpreted

Question 37

define a variable

Answer 37

ten=10

Question 38

print out the contents of the variable “ten”, also, what is a caviat with this that you should anticipate

Answer 38

echo $ten if the variable is a string with spaces, you’ll have to quote the variable in order to preserve it, e.g. echo “$ten”

Question 39

create an alias

Answer 39

alias ds=’cd ~/Dropbox’

Question 40

remove an alias

Answer 40

unalias ds

Question 41

temporarily ignore an alias

Answer 41

\ls (simply escape with backslash)