Basic Commands

06-14-2024

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Command line

Input and output

[zafar01@zmpt00 ~]$ pwd

/home/zafar01

pwd – print working directory

clear

- Clears the screen

[zafar01@zmpt00 ~]$ touch file1

touch

- Creates a file

- List the content of the directory

[zafar01@zmpt00 ~]$ ls

file1

ls -l

- -l is considered flag, it is used in combination of with ls

- Ls -l – this will show you long list information

[zafar01@zmpt00 ~]$ ls -l

total 0

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:52 file1

[zafar01@zmpt00 ~]$ touch file3 file4 file5

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ ls

file1 file2 file3 file4 file5

[zafar01@zmpt00 ~]$ ls -l

total 0

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:52 file1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:57 file2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

[zafar01@zmpt00 ~]$ touch x1 x2 x3 x4 x5

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ touch y1 y2 y3 y4 y5

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ ls -l

total 0

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:52 file1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:57 file2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x5

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y5

Use * to for filtering the files

[zafar01@zmpt00 ~]$ ls -l x*

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x5

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ ls -l f*

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:52 file1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:57 file2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

[zafar01@zmpt00 ~]$ ls -l *5

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x5

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y5

[zafar01@zmpt00 ~]$ ls -l *i*

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:52 file1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:57 file2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ ls -l *il*

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:52 file1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:57 file2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

Hidden files

- -a brings up hidden files

[zafar01@zmpt00 ~]$ ls -la

total 32

drwx------. 6 zafar01 zafar01 4096 Jun 14 09:02 .

drwxr-xr-x. 20 root root 4096 Jun 14 08:31 ..

-rw-------. 1 zafar01 zafar01 290 Jun 11 18:04 .bash_history

-rw-r--r--. 1 zafar01 zafar01 18 Nov 1 2022 .bash_logout

-rw-r--r--. 1 zafar01 zafar01 141 Nov 1 2022 .bash_profile

-rw-r--r--. 1 zafar01 zafar01 492 Nov 1 2022 .bashrc

[zafar01@zmpt00 ~]$ ls -la .x*

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:10 .xfile

[zafar01@zmpt00 ~]$ ls -la

total 32

drwx------. 6 zafar01 zafar01 4096 Jun 14 09:10 .

drwxr-xr-x. 20 root root 4096 Jun 14 08:31 ..

-rw-------. 1 zafar01 zafar01 290 Jun 11 18:04 .bash_history

-rw-r--r--. 1 zafar01 zafar01 18 Nov 1 2022 .bash_logout

-rw-r--r--. 1 zafar01 zafar01 141 Nov 1 2022 .bash_profile

-rw-r--r--. 1 zafar01 zafar01 492 Nov 1 2022 .bashrc

drwxr-xr-x. 10 zafar01 zafar01 4096 Jun 11 17:35 .cache

drwxr-xr-x. 9 zafar01 zafar01 4096 Jun 11 17:30 .config

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:52 file1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:57 file2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

drwx------. 4 zafar01 zafar01 32 Jun 11 17:24 .local

drwxr-xr-x. 4 zafar01 zafar01 39 Jun 11 16:51 .mozilla

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x5

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:10 .xfile

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y5

History

37 touch x1 x2 x3 x4 x5

38 touch y1 y2 y3 y4 y5

39 ls -l

40 clear

41 ls -l x*

42 ls -l

43 ls -l x*

44 ls -l f*

45 ls -l *5

46 ls -l *i*

47 ls -l *il*

48 clear

49 ls -la

50 clear

51 touch .xfile

52 ls

53 ls -a

54 ls -la .x*

55 ls -la

56 clear

57 history

58 clear

59 history

[zafar01@zmpt00 ~]$ !43

ls -l x*

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x5

- Remove files

[zafar01@zmpt00 ~]$ rm file1

[zafar01@zmpt00 ~]$ ls -l f*

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:57 file2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 08:59 file5

[zafar01@zmpt00 ~]$ rm f* < --- # Removes all files starting with f

[zafar01@zmpt00 ~]$ ls -l f*

ls: cannot access 'f*': No such file or directory

[zafar01@zmpt00 ~]$ rm *5

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ ls -l

total 0

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y4

[zafar01@zmpt00 ~]$ mkdir redh-hat

. < --- print working directory [present working directory]

├── redh-hat

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

[zafar01@zmpt00 ~]$ ls -al

total 32

drwx------. 7 zafar01 zafar01 4096 Jun 14 09:20 .

drwxr-xr-x. 20 root root 4096 Jun 14 08:31 ..

. Single dot is present working directory

.. two dot is the parent directory of present working directory

[zafar01@zmpt00 ~]$ tree

. < --- # parent directory of redh-hat [/home/zafar01]

├── redh-hat < --- # parent directory of black-hat

│ └── black-hat < --- # directory

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

2 directories, 8 files

[zafar01@zmpt00 ~]$ pwd

/home/zafar01

- cd is used to change the directory

Path

/home/zafar01/redh-hat

[zafar01@zmpt00 black-hat]$ pwd

/home/zafar01/redh-hat/black-hat

Absolute path

/home/zafar01/redh-hat/black-hat

[zafar01@zmpt00 black-hat]$ pwd

/home/zafar01/redh-hat/black-hat

[zafar01@zmpt00 black-hat]$

[zafar01@zmpt00 black-hat]$ cd .. < -- # takes you one level to parent of directory

[zafar01@zmpt00 redh-hat]$ cd .. < -- # takes you one level to parent of directory

[zafar01@zmpt00 ~]$ pwd

/home/zafar01

Relative path for black-hat directory

redh-hat/black-hat/

[zafar01@zmpt00 ~]$ cd redh-hat/black-hat/

[zafar01@zmpt00 black-hat]$ pwd

/home/zafar01/redh-hat/black-hat

- simply typing cd make you jump to your home directory

Changing directory using absolute path

[zafar01@zmpt00 ~]$ cd /home/zafar01/redh-hat/black-hat

[zafar01@zmpt00 black-hat]$ pwd

/home/zafar01/redh-hat/black-hat

- this is copy command

Copy using relative path

Command	Source	Destination [relative path]
cp	x1	/redh-hat/black-hat/

[zafar01@zmpt00 ~]$ cp x1 redh-hat/black-hat/

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ └── black-hat

│ └── x1

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

2 directories, 9 files

Copy using absolute path

Command	Source	Destination [absolute path]
cp	x1	/home/zafar01/redh-hat/black-hat/

cp x2 /home/zafar01/redh-hat/black-hat/

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ └── black-hat

│ ├── x1

│ └── x2

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

2 directories, 10 files

Copying multiple files

[zafar01@zmpt00 ~]$ cp x* /home/zafar01/redh-hat

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ ├── black-hat

│ │ ├── x1

│ │ ├── x2

│ │ ├── x3

│ │ └── x4

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

- this is move command

- files physically get moved

[zafar01@zmpt00 ~]$ mv y* /home/zafar01/redh-hat/black-hat/

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ ├── black-hat

│ │ ├── x1

│ │ ├── x2

│ │ ├── x3

│ │ ├── x4

│ │ ├── y1

│ │ ├── y2

│ │ ├── y3

│ │ └── y4

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── x1

├── x2

├── x3

└── x4

2 directories, 16 files

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ mv /home/zafar01/redh-hat/black-hat/y* .

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ ├── black-hat

│ │ ├── x1

│ │ ├── x2

│ │ ├── x3

│ │ └── x4

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

[zafar01@zmpt00 ~]$ mkdir white-hat

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ ├── black-hat

│ │ ├── x1

│ │ ├── x2

│ │ ├── x3

│ │ └── x4

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── white-hat < --- new directory in my home directory

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

Move entire directory

Command	Source	Destination [absolute path]
mv	redh-hat/black-hat/	white-hat/

[zafar01@zmpt00 ~]$ mv redh-hat/black-hat/ white-hat/

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── white-hat

│ └── black-hat

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

3 directories, 16 files

Relative path

Command	Source	Destination [absolute path]
cp -r	white-hat/black-hat/	redh-hat/

Absolute path

Command	Source	Destination [absolute path]
cp -r	/home/zafar01/white-hat/black-hat/	/home/zafar01/redh-hat/

[zafar01@zmpt00 ~]$ cp -r white-hat/black-hat/ redh-hat/

[zafar01@zmpt00 ~]$ tree

├── redh-hat

│ ├── black-hat

│ │ ├── x1

│ │ ├── x2

│ │ ├── x3

│ │ └── x4

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── white-hat

│ └── black-hat

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

4 directories, 20 files

06-21-2025

Video recording – open in new tab

Ccho

- this command repeats the text as output

[zafar01@zmpt00 ~]$ echo

[zafar01@zmpt00 ~]$ echo this is linux course

this is linux course

Running multiple commands

[zafar01@zmpt00 ~]$ echo this is pwd;pwd;echo this is ls -l;echo;ls -l;echo this is tree;echo;tree

this is pwd

/home/zafar01

this is ls -l

total 0

drwxr-xr-x. 3 zafar01 zafar01 63 Jun 14 10:40 redh-hat

drwxr-xr-x. 3 zafar01 zafar01 23 Jun 14 10:38 white-hat

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y4

this is tree

├── redh-hat

│ ├── black-hat

│ │ ├── x1

│ │ ├── x2

│ │ ├── x3

│ │ └── x4

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── white-hat

│ └── black-hat

│ ├── x1

│ ├── x2

│ ├── x3

│ └── x4

├── x1

├── x2

├── x3

├── x4

├── y1

├── y2

├── y3

└── y4

4 directories, 20 files

Alias

- you can create your own command

- This is good for running multiple commands

[zafar01@zmpt00 ~]$ alias zafar="ls -l; pwd;"

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ zafar

total 0

drwxr-xr-x. 3 zafar01 zafar01 63 Jun 14 10:40 redh-hat

drwxr-xr-x. 3 zafar01 zafar01 23 Jun 14 10:38 white-hat

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y4

/home/zafar01

[zafar01@zmpt00 ~]$ alias

alias egrep='egrep --color=auto'

alias fgrep='fgrep --color=auto'

alias grep='grep --color=auto'

alias l.='ls -d .* --color=auto'

alias ll='ls -l --color=auto'

alias ls='ls --color=auto'

alias xzegrep='xzegrep --color=auto'

alias xzfgrep='xzfgrep --color=auto'

alias xzgrep='xzgrep --color=auto'

alias zafar='ls -l; pwd;'

alias zegrep='zegrep --color=auto'

alias zfgrep='zfgrep --color=auto'

alias zgrep='zgrep --color=auto'

To remove alias

[zafar01@zmpt00 ~]$ unalias zafar

VI editor

vi text-file

- i #< -- to enter the edit mode

- esc #< -- this will exit edit mode and put you in command mode

esc

save and exit the file

cat

- this command reads the content of the file

[zafar01@zmpt00 ~]$ cat text-file

this is linux

this is vi editor

today is saturday

Commonly used vi editor commands

- dd deletes the line where the cursor is located

- o opens new line in insert mode

- esc #< ------ this will exit edit mode and put you in command mode

- q #< --------- quits the file, when no changes were made

- q! #< --------- quits discarding changes, if you have edited the file

- yy #< ---------- copies the line where the cursor is

- u #< --------- undo your last action

- x #< --------- deletes the letter where ever is present

- /linux #< --------- searches for the pattern in the file

- :%s/linux/RED-HAT #< --- %s invokes search /linux - pattern - /RED-HAT replaced word

- :set number #< --- enables the line number

‘:e file1’	Loads the specified file for editing - You can also specifi absolute and relative path
‘:r’	Load the file content of the file again
:!	Allows you to run shell commands from within vi example: !ls /etc
i	insert text and not replace it
R	over write existing text when new text added
cw	remove current word cursor is on and insert into insert mode to add text
cc	replace the entire of line of text
l	moves cursor one character to the right
h	moves cursor one character to the left
j	moves cursor down one line
k	moves cursor up one line Yank – Term used to copy text. Use YY to “yank” a line of text.
yy	will yank/copy entire line the cursor is currently on
2yy	will copy the current line of text as well as the line underneath it (2lines)
3yy	will copy three lines, 4yy 4 lines of text 5yy…
p	will paste the contents from yanked yy text, starting on the line after your cursor
P	uppercase P will paste the yanked line(s) starting on the line before the cursor
5G	moves your cursor to line 5
5gg	moves your cursor to line 5 (note case sensitive)
G	Moves the cursor to the beginning of the last line in the file
1G	Moves the cursor to the first line of the file
L	Also moves the cursor to the beginning of the last line on the terminal screen
H	Moves the cursor to the first line on the terminal screen
o	opens insert mode to insert text, creates a new line below your current cursor position
u	undo
cc	Removes the entire line and places you into insert mode

cat

- Concatenate – it reads the file and display the output

[zafar01@zmpt00 ~]$ cat text-file

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

Redirector

Three important redirectors

0	<	Standard input
1	>	Standard output
2	2>	Standard error / captures the errors

Standard input

[zafar01@zmpt00 ~]$ cat text-file

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

[zafar01@zmpt00 ~]$ cat 0< text-file

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

Standard output

[zafar01@zmpt00 ~]$ cat text-file

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

[zafar01@zmpt00 ~]$ cat text-file 1> x1

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ cat x1

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

[zafar01@zmpt00 ~]$ cat text-file >> x1 #< --- this double >> adds to the end of the file

[zafar01@zmpt00 ~]$ cat x1

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

[zafar01@zmpt00 ~]$ cat text-file > x1 #< -- this single > overwrites the file

[zafar01@zmpt00 ~]$ cat x1

this is RED-HAT

this is vi editor

today is saturday

this is RED-HAT

Standard error

[zafar01@zmpt00 ~]$ ls -l /home/*

ls: cannot open directory '/home/abdul01': Permission denied

ls: cannot open directory '/home/abrar01': Permission denied

ls: cannot open directory '/home/ahmed01': Permission denied

ls: cannot open directory '/home/akram01': Permission denied

ls: cannot open directory '/home/bit01': Permission denied

ls: cannot open directory '/home/bruce01': Permission denied

ls: cannot open directory '/home/gregory01': Permission denied

ls: cannot open directory '/home/jony01': Permission denied

ls: cannot open directory '/home/khader01': Permission denied

ls: cannot open directory '/home/kumar01': Permission denied

ls: cannot open directory '/home/luis01': Permission denied

ls: cannot open directory '/home/mohamed01': Permission denied

ls: cannot open directory '/home/mubashir01': Permission denied

ls: cannot open directory '/home/muhamadou01': Permission denied

ls: cannot open directory '/home/rexford01': Permission denied

ls: cannot open directory '/home/samuel01': Permission denied

ls: cannot open directory '/home/sarmila01': Permission denied

ls: cannot open directory '/home/sidney01': Permission denied

/home/zafar01:

total 12

drwxr-xr-x. 3 zafar01 zafar01 63 Jun 14 10:40 redh-hat

-rw-r--r--. 1 zafar01 zafar01 85 Jun 21 09:29 text-file

drwxr-xr-x. 3 zafar01 zafar01 23 Jun 14 10:38 white-hat

-rw-r--r--. 1 zafar01 zafar01 85 Jun 21 10:09 x1

-rw-r--r--. 1 zafar01 zafar01 2224 Jun 21 10:14 x2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y1

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y3

What 2> sing does is, it filters out any errors and show you good out put

For this to be working, you have send it to a file or /dev/null

File – if you need to analyze the errors output

/dev/null – if you don’t care about error output

find

- Find command file you looking in a directory

Command	Directory	Using name	File name
find	.	-name	text-file

[zafar01@zmpt00 ~]$ find . -name text-file

./text-file

[zafar01@zmpt00 ~]$ find /home -name text-file

/home/zafar01/text-file

find: ‘/home/bit01’: Permission denied

find: ‘/home/bruce01’: Permission denied

find: ‘/home/sidney01’: Permission denied

find: ‘/home/muhamadou01’: Permission denied

find: ‘/home/sarmila01’: Permission denied

find: ‘/home/luis01’: Permission denied

find: ‘/home/gregory01’: Permission denied

find: ‘/home/jony01’: Permission denied

find: ‘/home/mubashir01’: Permission denied

find: ‘/home/abdul01’: Permission denied

find: ‘/home/rexford01’: Permission denied

find: ‘/home/samuel01’: Permission denied

find: ‘/home/abrar01’: Permission denied

find: ‘/home/khader01’: Permission denied

find: ‘/home/ahmed01’: Permission denied

find: ‘/home/akram01’: Permission denied

find: ‘/home/mohamed01’: Permission denied

find: ‘/home/kumar01’: Permission denied

[zafar01@zmpt00 ~]$ find /home -name text-file 2> /dev/null

/home/zafar01/text-file

File is a file

Folder is also a file

Find using inode

Command	location	Using inode	Inode number	Std error	Discard dir
find	/	-inum	35416378	2>	/dev/null

[zafar01@zmpt00 ~]$ ls -i text-file

35416378 text-file

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ find /home -inum 35416378 2> /dev/null

/home/zafar01/text-file

[zafar01@zmpt00 ~]$

[zafar01@zmpt00 ~]$ find / -inum 35416378 2> /dev/null

/home/zafar01/text-file

grep

- Use to search the specific word in the file

- Use it as filter to give you output

- It matches the pattern

[zafar01@zmpt00 ~]$ cat text-file

total 24

drwx------. 3 abdul01 abdul01 78 Jun 14 07:05 abdul01

drwx------. 3 abrar01 abrar01 78 Jun 14 07:05 abrar01

drwx------. 3 ahmed01 ahmed01 78 Jun 14 07:05 ahmed01

drwx------. 3 akram01 akram01 78 Jun 14 07:24 akram01

drwx------. 5 bit01 bit01 191 Jun 21 10:16 bit01

drwx------. 3 bruce01 bruce01 78 Jun 14 07:05 bruce01

drwx------. 6 gregory01 gregory01 4096 Jun 21 10:38 gregory01

drwx------. 6 jony01 jony01 4096 Jun 21 10:10 jony01

drwx------. 5 khader01 khader01 4096 Jun 14 10:44 khader01

drwx------. 3 kumar01 kumar01 78 Jun 21 08:17 kumar01

drwx------. 3 luis01 luis01 78 Jun 14 07:05 luis01

drwx------. 5 mohamed01 mohamed01 134 Jun 14 08:50 mohamed01

drwx------. 3 mubashir01 mubashir01 78 Jun 14 07:05 mubashir01

drwx------. 7 muhamadou01 muhamadou01 4096 Jun 20 21:48 muhamadou01

drwx------. 3 rexford01 rexford01 113 Jun 21 10:05 rexford01

drwx------. 3 samuel01 samuel01 190 Jun 21 10:37 samuel01

drwx------. 9 sarmila01 sarmila01 4096 Jun 14 10:44 sarmila01

drwx------. 3 sidney01 sidney01 78 Jun 14 07:05 sidney01

drwx------. 8 zafar01 zafar01 4096 Jun 21 09:29 zafar01

[zafar01@zmpt00 ~]$ cat text-file | grep greg

drwx------. 6 gregory01 gregory01 4096 Jun 21 10:38 gregory01

-i – Ignores case

[zafar01@zmpt00 ~]$ cat text-file | grep -i greg

drwx------. 6 gregory01 gregory01 4096 Jun 21 10:38 gregory01

GREGORY

[zafar01@zmpt00 ~]$

- Wod count

[zafar01@zmpt00 ~]$ wc text-file

23 176 1260 text-file

Lines	words	Characters	File name
23	176	1260	text-file

06-29-2025

Video Recording – open in new tab

Head

- This command will read the file, but output will by default be 10 lines

- You can use head to many lines as possible

- But will start from first line

[zafar01@zmpt00 ~]$ head -15 text-file # < -- show top 15 lines

[zafar01@zmpt00 ~]$ head -5 text-file # < -- show top 5 lines

Tail

- Reads the bottom 10 lines by default

- You can add switch for the desired number of lines

- Tail -5 – display bottom 5 lines

- Tail –f to view the real-time activity of the file

- Example /var/log/secure

[zafar01@zmpt00 ~]$ tail -5 text-file # < -- show bottom 5 lines

[zafar01@zmpt00 ~]$ tail -15 text-file # < -- show bottom 15 lines

To see the live activity of a file use tail -f

[zafar01@zmpt00 ~]$ sudo tail -f /var/log/secure

sort

- This command will sor the output in alphabetical order

[zafar01@zmpt00 ~]$ sort sort-file

[zafar01@zmpt00 ~]$ sort -r sort-file # < --- sorts in reverse order

[zafar01@zmpt00 ~]$ awk '{print $3, $4}' sort-file

column3 column4

[zafar01@zmpt00 ~]$ awk '{print $3, $4,$1,$2,$1}' sort-file

column3 column4 column1 column2 column1

[zafar01@zmpt00 ~]$ awk '{print $3," " $4}' sort-file # < -- use quote and space to add space to output

column3 column4

[zafar01@zmpt00 ~]$ uniq sort-file

column1 column2 column3 column4

column2 column2 column3 column4

column1 column2 column3 column4

column4 column3 column2 column1

column3 column3 column2 column1

[zafar01@zmpt00 ~]$ date

Sat Jun 28 08:57:05 AM CDT 2025

[zafar01@zmpt00 ~]$ cal

June 2025

Su Mo Tu We Th Fr Sa

1 2 3 4 5 6 7

8 9 10 11 12 13 14

15 16 17 18 19 20 21

22 23 24 25 26 27 28

29 30

[zafar01@zmpt00 ~]$ cal 09 2025

September 2025

Su Mo Tu We Th Fr Sa

1 2 3 4 5 6

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26 27

28 29 30

W or who

- Displays who is logged in

Last

- Displays the login activity of users

[zafar01@zmpt00 ~]$ free -h

total used free shared buff/cache available

Mem: 1.7Gi 809Mi 427Mi 46Mi 747Mi 961Mi

Swap: 2.0Gi 0B 2.0Gi

[zafar01@zmpt00 ~]$

- Disk usage

- Displays the size of the file or folder

du	-hx	.	--max-depth=1
Command	Human readeable	Pwd	Level of depth it will check

[zafar01@zmpt00 redh-hat]$ du -hx . --max-depth=1

0 ./black-hat

0 ./white-hat

4.4M .

[zafar01@zmpt00 redh-hat]$ ls -ltrh

total 4.3M

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 x3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y4

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y3

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y2

-rw-r--r--. 1 zafar01 zafar01 0 Jun 14 09:02 y1

drwxr-xr-x. 3 zafar01 zafar01 23 Jun 14 10:38 white-hat

drwxr-xr-x. 2 zafar01 zafar01 46 Jun 14 10:40 black-hat

-rw-r--r--. 1 zafar01 zafar01 85 Jun 21 10:09 x1

-rw-r--r--. 1 zafar01 zafar01 2.2K Jun 21 10:14 x2

-rw-r--r--. 1 zafar01 zafar01 1.3K Jun 21 10:51 text-file

-rw-r--r--. 1 zafar01 zafar01 388 Jun 28 09:03 sort-file

-rw-r--r--. 1 zafar01 zafar01 121 Jun 28 09:05 new-sort-file

-rwxr-xr-x. 1 root root 365K Jun 28 09:10 messages

-rw-r--r--. 1 zafar01 zafar01 4.0M Jun 28 09:13 messages1

[zafar01@zmpt00 redh-hat]$ top

top - 09:17:31 up 14 days, 17:17, 7 users, load average: 0.00, 0.00, 0.00

Tasks: 196 total, 1 running, 194 sleeping, 1 stopped, 0 zombie

%Cpu(s): 0.7 us, 1.7 sy, 0.0 ni, 97.4 id, 0.0 wa, 0.3 hi, 0.0 si, 0.0 st

MiB Mem : 1771.1 total, 192.9 free, 899.7 used, 907.2 buff/cache

MiB Swap: 2048.0 total, 2048.0 free, 0.0 used. 871.4 avail Mem

97.4 id – this means that 97% of the CPU is idle [not busy]

%Cpu(s): 2.7 us, 1.7 sy, 0.0 ni, 95.3 id, 0.0 wa, 0.3 hi, 0.0 si, 0.0 st

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

189703 root 20 0 19352 11308 9288 S 1.7 0.6 0:00.05 sshd

189713 bit01 20 0 229632 9436 6212 S 1.7 0.5 0:00.05 vim

189516 zafar01 20 0 225900 4128 3500 R 0.7 0.2 0:01.69 top

189526 gregory+ 20 0 226032 4216 3356 S 0.7 0.2 0:01.51 top

189614 samuel01 20 0 225900 4004 3376 S 0.7 0.2 0:03.19 top

16 root 20 0 0 0 0 R 0.3 0.0 0:18.13 rcu_preempt

791 root 20 0 193320 18264 10856 S 0.3 1.0 3:03.97 rsyslogd

187454 bit01 20 0 224224 6000 3884 S 0.3 0.3 0:00.96 bash

187562 gregory+ 20 0 19520 7408 5112 S 0.3 0.4 0:01.16 sshd

189113 samuel01 20 0 19520 7364 5068 S 0.3 0.4 0:00.93 sshd

1 root 20 0 106588 16348 10420 S 0.0 0.9 1:36.16 systemd

[zafar01@zmpt00 redh-hat]$ lscpu

Architecture: x86_64

CPU op-mode(s): 32-bit, 64-bit

Address sizes: 36 bits physical, 48 bits virtual

Byte Order: Little Endian

CPU(s): 1

Which

- this command will show you the location of the command or package

- also a good indication if a command or package is installed

[zafar01@zmpt00 ~]$ which pwd

/usr/bin/pwd

[zafar01@zmpt00 ~]$ which firefox

/usr/bin/which: no firefox in (/home/zafar01/.local/bin:/home/zafar01/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin)

Pipe

- | this is a pipe key

- Pipe is used for run multiple commands

Primary command | secondary command | thrid commands

[zafar01@zmpt00 redh-hat]$ cat furits | grep apple

apple

pineapple

[zafar01@zmpt00 redh-hat]$ cat furits | grep apple | grep pine

pineapple

[zafar01@zmpt00 redh-hat]$ cat furits | grep Apple

[zafar01@zmpt00 redh-hat]$ cat furits | grep -i Apple

apple

pineapple

gzip

- Gzip is used for zipping file and compressing[reducing size] it

- It adds the extension .gz

[zafar01@zmpt00 redh-hat]$ ls -ltrh messages1

-rw-r--r--. 1 zafar01 zafar01 11M Jun 28 10:01 messages1

[zafar01@zmpt00 redh-hat]$ gzip messages1

-rw-r--r--. 1 zafar01 zafar01 748K Jun 28 10:01 messages1.gz #< -- adds extension .gz

Messages1 is now at under 1MB from being 11 MB

Gunzip

- Unzips and uncompresses the file

- Removes .gz extension

- Restores to original form

[zafar01@zmpt00 redh-hat]$ ls -ltrh messages1

-rw-r--r--. 1 zafar01 zafar01 11M Jun 28 10:01 messages1

tar

- It convers the folder to a single file and adds .tar extension

- It does not compressess or reduce the size of a folder

- Its keeps the origiznal folder as is but creates another file with .tar extension

C – create

V – verbose [show you on screen what is being tar]

F - folder

tar	-cvf	redh-hat.tar	redh-hat
Command	Switch	Destination	source

[zafar01@zmpt00 ~]$ tar -cvf redh-hat.tar redh-hat/

redh-hat/

redh-hat/x1

redh-hat/x2

redh-hat/x3

redh-hat/x4

redh-hat/black-hat/

redh-hat/black-hat/x1

redh-hat/black-hat/x2

redh-hat/black-hat/x3

redh-hat/black-hat/x4

redh-hat/new-sort-file

redh-hat/sort-file

redh-hat/text-file

redh-hat/white-hat/

redh-hat/white-hat/black-hat/

redh-hat/white-hat/black-hat/x1

redh-hat/white-hat/black-hat/x2

redh-hat/white-hat/black-hat/x3

redh-hat/white-hat/black-hat/x4

redh-hat/y1

redh-hat/y2

redh-hat/y3

redh-hat/y4

redh-hat/messages

redh-hat/furits

redh-hat/messages1

total 780K

drwxr-xr-x. 4 zafar01 zafar01 4.0K Jun 28 10:04 redh-hat

-rw-r--r--. 1 zafar01 zafar01 774K Jun 28 10:07 redh-hat.tar.gz

[zafar01@zmpt00 ~]$ rm -rf redh-hat

X – extract

V – verbose

F - folder

[zafar01@zmpt00 ~]$ tar -xvf redh-hat.tar.gz

redh-hat/

redh-hat/x1

redh-hat/x2

redh-hat/x3

redh-hat/x4

redh-hat/black-hat/

redh-hat/black-hat/x1

redh-hat/black-hat/x2

redh-hat/black-hat/x3

redh-hat/black-hat/x4

redh-hat/new-sort-file

redh-hat/sort-file

redh-hat/text-file

redh-hat/white-hat/

redh-hat/white-hat/black-hat/

redh-hat/white-hat/black-hat/x1

redh-hat/white-hat/black-hat/x2

redh-hat/white-hat/black-hat/x3

redh-hat/white-hat/black-hat/x4

redh-hat/y1

redh-hat/y2

redh-hat/y3

redh-hat/y4

redh-hat/messages

redh-hat/furits

redh-hat/messages1

[zafar01@zmpt00 ~]$ ls -l

total 780

drwxr-xr-x. 4 zafar01 zafar01 4096 Jun 28 10:04 redh-hat

-rw-r--r--. 1 zafar01 zafar01 792039 Jun 28 10:07 redh-hat.tar.gz

Stat

- Displays detailed informaiton regarding file or folder

- Important informaiton to consider is inode

[zafar01@zmpt00 ~]$ stat redh-hat.tar.gz

File: redh-hat.tar.gz

Size: 792039 Blocks: 1552 IO Block: 4096 regular file

Device: fd00h/64768d Inode: 35657439 Links: 1

Access: (0644/-rw-r--r--) Uid: ( 1000/ zafar01) Gid: ( 1000/ zafar01)

Context: unconfined_u:object_r:user_home_t:s0 [selinux]

Access: 2025-06-28 10:14:14.885562820 -0500

Modify: 2025-06-28 10:07:36.311768694 -0500

Change: 2025-06-28 10:11:29.581403990 -0500

Birth: 2025-06-28 10:11:29.134400851 -0500

Inode

Inode: 35657439

It a table on the disk that holds the file information

Owner of the file

Group of the file

Type of the file – file or directory

Permissions

Date and time of the file modified, created, accessed etc.,

Number of links

Block information

Links

- Two types of links for a file

- Hard link and soft link

Hard link

- It has same inode number

- You have to provide source and destination absolute paths

- Any change to content of the file will be updated on both files

- Hard linke files are essentially duplicates fo each other

- If the original fiel si deleted, then hard linked file will survive

- Hard link for directories are not allowed

[zafar01@zmpt00 ~]$ ln redh-hat/furits furits-1

ln	redh-hat/furits	furits-1
Command	Source	Densination

Location and name can have variation

Hard linked files have same inode

They are essentially duplicate of each other

Any updates on either side, updates both

If one is deleted, other survives with data

[zafar01@zmpt00 ~]$ ls -i furits-1

822965 furits-1

[zafar01@zmpt00 ~]$ ls -i redh-hat/furits

822965 redh-hat/furits

[zafar01@zmpt00 ~]$ rm -rf redh-hat/furits #< --- delete original file

[zafar01@zmpt00 ~]$ ls -i redh-hat/furits

ls: cannot access 'redh-hat/furits': No such file or directory

[zafar01@zmpt00 ~]$ ls -i furits-1

822965 furits-1

[zafar01@zmpt00 ~]$ cat furits-1 #< --- hard linked file survived

apple

buleberry

blueberry

orange is citrus

strawberry

pineapple

I am adding this line from hard link

this is test

Softlink

- Referred to as symbolic link or sym link

- You have to provide ABSOLUTE path for the soruce and destination

- Soft link has different inode number

- Most of the time soft link is used to grant read access to user or application to a restricted file

- Updating soft link – updates origianl file

- Delting original file will render soft link useless

- Soft is allowd for directories