Bash

Question 1

Bash: how to delete from cursor to beginning of word?

Answer 1

ctrl-w

Question 2

Bash: how to jump to end of line?

Answer 2

ctrl-e

Question 3

Bash: how to jump to the beginning of line?

Answer 3

ctrl-a

Question 4

Bash: how to jump one word backwards?

Answer 4

alt-b

Question 5

Bash: how to jump one word forwards?

Answer 5

alt-f

Question 6

Bash: how to delete from cursor to end of line?

Answer 6

ctrl-k

Question 7

Bash: how to delete from cursor to beginning of line?

Answer 7

ctrl-u

Question 8

Bash: how to go to previous directory (.bashrc shorthand)?

Answer 8

$ bd

Question 9

Bash: how to go to previous directory with builtin?

Answer 9

$ cd -

Question 10

Bash: how to do arithmetic calculations?

Answer 10

$(( expression ))

Question 11

Bash: how to reuse argument of previous command?

Answer 11

!$
or
!:1

Example:
$ ls hello
$ ls !$

Question 12

Bash: how to paste from special clipboard (ctrl-u & k use)?

Answer 12

ctrl-y

Question 13

Bash: how to save output of command to file (overwrite)?

Answer 13

$ cmd > filename

Question 14

Bash: how to save output of command to file (append)?

Answer 14

$ cmd&raquo_space; filename

Question 15

Bash: which command argument is usually used to display output (expanded format) before execution?

Answer 15

-x

Question 16

Bash: how to display history of commands?

Answer 16

$ history

Question 17

Bash: after displaying history - how to execute command by number?

Answer 17

$ !83

Question 18

Bash: how to execute/reference previous command?

Answer 18

$ !!
or
$ !-1

Example:
$ echo /etc/test
$ sudo !!

Question 19

Bash: How to execute command from history by keywords?

Answer 19

$ !?keyword

Question 20

Bash: how to replace words from previous command (for example create file and view content)?

Answer 20

^search^replace^

Question 21

Bash: how to get the first argument of a command starting with x?

Answer 21

!keyword:^

Example:
$ ls test
$ cd hallo
$ ls !ls:^

Question 22

Bash: how to get filename of path from previous command?

Answer 22

!!:$:t

Example:
$ cat /etc/test/hallo.txt
$ vim !!:$:t
returns: hallo.txt

Question 23

Bash: how to delete extension from path from previous command?

Answer 23

!!:$:r

Example:
$ cat /etc/test/hallo.txt
$ vim !!:$:t
returns: /etc/test/hallo

Question 24

Bash: How to do sed like substitution of previous command?

Answer 24

!!:s/search/replace

Question 25

Bash: how to repeat previous substitution on previous command?

Answer 25

!!:g&

& becomes a and sign (has been escaped)

Question 26

Bash: how to print substition before executing it?

Answer 26

append “:p” to substitution

Question 27

Bash: how to change 3 directories up (own helper in .bashrc)

Answer 27

$ ….

Question 28

Bash: how to change 2 directories up (own helper in .bashrc)

Answer 28

$ …

Question 29

Bash: how to change 1 directory up (own helper in .bashrc)

Answer 29

$ ..

Question 30

Bash: how to securely clear the screen of terminals?

Answer 30

$ clear

Question 31

Bash: how to append text found by delimiter of another file into another file (heredocument syntax)?

Answer 31

$ cat&raquo_space; path/to/file &laquo_space;””

Question 32

Bash: how to save current directory as name “test” to bashmarks?

Answer 32

$ s test

Question 33

Bash: how to list all bashmarks folders and names?

Answer 33

$ l

Question 34

Bash: how to go to bashmark with name test?

Answer 34

$ g test

Question 35

Bash: how to get the first column of output?

Answer 35

$ | awk -v col=1 ‘{print $col}’

Question 36

Bash: how to create directories for folder names inside file?

Answer 36

for a in cat ./dirs; do mkdir $a; done

Question 37

Bash: what is xargs used for?

Answer 37

It is used to build and execute command lines from standard input. For example:
$ cat dirs | xargs mkdir
will use cat to take the strings (be it newline or blank character separated) from file ‘dirs’ and pass them through pipe to xargs which will then send one by one line as argument to mkdir which will then create those dirs or complain if those are existent.

Question 38

Bash: how to delete filename (get folder) from path of previous command?

Answer 38

!!:$:h

Example:
$ cat /test/hallo.txt
$ cd !!:$:h

Question 39

Bash: how to get the first argument of the previous command?

Answer 39

!!:^

Question 40

Bash: how to jump between start of line and cursor position?

Answer 40

ctrl-xx

Question 41

Bash: how to delete from cursor to end of word?

Answer 41

alt-d

Question 42

Bash: how to swap character with previous one?

Answer 42

ctrl-t

Question 43

Bash: how to delete character before cursor?

Answer 43

ctrl-h

Question 44

Bash: how to delete character under cursor?

Answer 44

ctrl-d

Question 45

Bash: how to enter the search mode in history by keywords?

Answer 45

ctrl-r

Question 46

Bash: how to get the previous command (instead of arrow up)?

Answer 46

ctrl-p

Question 47

Bash: how to get the next command (instead of arrow down)?

Answer 47

ctrl-n

Question 48

Bash: how to get the last word of the previous command with shortcuts?

Answer 48

alt-.

Question 49

Bash: how to make lowercase from cursor to end of word?

Answer 49

alt-l

Question 50

Bash: how to make uppercase from cursor to end of word?

Answer 50

alt-u

Question 51

Bash: how to run a command found in history mode (ctrl-r)?

Answer 51

ctrl-o

Question 52

Bash: how to scroll one line up?

Answer 52

ctrl-shift-arrow up

Question 53

Bash: how to scroll one line down?

Answer 53

ctrl-shift-arrow down

Question 54

Bash: how to swap word with previous one?

Answer 54

alt-t

Question 55

Bash: how to remove preceding path from filename in variable f?

Answer 55

${f##*/}

Question 56

Bash: how to remove extension from filename in variable f?

Answer 56

${f%.*}

Question 57

Bash: how to replace string in variable (first occurance)?

Answer 57

${variable/search/replace}

${$var… not working!

Question 58

Bash: how to remove string at beginning of variable?

Answer 58

${var#string_to_remove}

Question 59

Bash: how to remove string at end of variable?

Answer 59

${var%string_to_remove}

Question 60

Bash: how to replace all occurances of search with replace in variable?

Answer 60

${variable//search/replace}

${$var… not working!

Question 61

Bash: how to get the Process ID of a process with name “x”?

Answer 61

pidof x

Question 62

Bash: how to kill process with id x?

Answer 62

kill x

Question 63

Bash: how to kill process listening on port?

Answer 63

fuser -n tcp -k 9001

Question 64

Bash: how to copy files an rename?

Answer 64

for file in bin/docker-create-build-*.in; do cp $file ${file/local/live}; done

Question 65

Bash: how to get files which changed in the last 2 mins?

Answer 65

find . -mmin -2 -type f print

Question 66

Bash: How to search for string starting with “test” and only print the match?

Answer 66

echo “test32. 23232. 23232” | grep -o ‘test[^\s]*’

Question 67

Bash: How to get item index 0 from array x?

Answer 67

${x[0]}

Question 68

Bash: How to iterate over an array with a for loop counting the index?

Answer 68

for ((x = 0; x < ${#array[@]}; x++)); then…

Question 69

Bash: how to fer the exit status of decent Command?

Answer 69

$?

Question 70

Bash: how to get the Process id of a Bash Command ein in background?

Answer 70

it Returns the process id

Question 71

Bash: How to list directories recursively?

Answer 71

find . -type d -print

Question 72

Bash: how to list files recursively?

Answer 72

find . -type f -print

Question 73

Bash: how to remove all files execpt?

Answer 73

rm -r !(file1|file2)