Terminal 101

Question 1

man [command]

Answer 1

displays manual of specific commands

Question 2

[command] –h

Answer 2

displays a short description of the command

Question 3

pwd

Answer 3

prints working directory

Question 4

cd

Answer 4

Changes directory.
[cd - ] to navigate back to the previous working directory
[cd, cd ~] to navigate to the home directory
[cd / ] to navigate to the root directory
[cd .. ] to navigate back of one directory

Question 5

ls

Answer 5

Lists contents of current w.d
[-l] lists contents in a table format
[-t] lists contents based on the timestamp

Question 6

*

Answer 6

Allows to select file or directory names based on patterns
[] all files
[b] all files starting with b
[b.txt] all files starting with b and ending with .txt
[[abc]] all files starting with a b or c

Question 7

?

Answer 7

Allows for one char to have any value

Question 8

cp

Answer 8

copies files or directories
[cp file1 file2]creates file2 and copies contents of file1 into it
[cp file1 file2 dir1] copies file1/2 into dir1
[cp dir1/* dir2] copies all files from dir1 to dir 2
[cp -r dir1/* dir2] copies all files and directories of dir1 into dir2

Question 9

mv

Answer 9

Moves files and directories
[mv file1 file2]
- renames file1 to file2
- moves file1 to file2 (which is overwritten if already existing)
[mv file1 file2 dir1] moves file1/2 into dir1 (must already exist)
[mv dir1 dir2] moves all files from dir1 to dir 2 (dir1 is erased)

Question 10

rm

Answer 10

Removes files or directories
[rm file1]
[rm -r dir1]

Question 11

mkdir [directory_name]

Answer 11

creates directory in current w.d

Question 12

touch [file_name]

Answer 12

Updates timestamp of the file
[touch -a file1] updates last access timestamp
[touch -m file1] updates last modified timestamp

Question 13

-i & -n

Answer 13

[-i] adds a prompt to confirm the action before modifying a file
[-n] defines that no files can be overwritten

Question 14

cat

Answer 14

Concatenates files
[cat file1] shows the contents of file1
[cat > file1] will create file1 + add contents through terminal prompt
[cat -n file1] prints file contents with line numbers
[cat file1 > file2] creates or overwrites file2 with contents of file1
[cat file1&raquo_space; file2] appends contents of file1 to file2
[cat file1 file2 | sort > file4] sorts contents of file1 and file2 and appends to file4

Question 15

uniq

Answer 15

removes duplicate files or contents

Question 16

grep [“pattern”] file1

Answer 16

Prints lines containing “pattern” in file1
[-i] ignores case
[-r] recursive search (into sub dir)
[-c] outputs number of times pattern was found in file1

Question 17

echo

Answer 17

[echo “text”] outputs text
[echo $VAR] outputs value of var
[echo *] outputs all files or directories in w.d
[echo “text” > file1] writes or overwrites text into file1
[echo “text”&raquo_space; file1] appends text into file1