Linux Free Basic To Advance Command Full Course
1) Which command in Linux is used to print information about the system and its
environment?
->$ uname
2)Which command in Linux is used to get more info about the system?
->$ uname -a
3)Which command is used to print the ip address?
->$ ifconfig
4)If ifconfig is not getting recognized by the system then which package we have
to install,again what will be the command?
->$ sudo yum install net-tools
5)How to check the user-name in linux?
->$ whoami
6)How to check the machine os,which command is used?
->$ cat /etc/os-release
7)How to print the shell name?
->$ echo $SHELL or $echo $0
8)Which command in Linux is used to determine the execution time of a given
command or process? Also give one example.
->$ time command_name
Example:-time ls
9)Which command is used to list down all the available shells ?
->$ cat /etc/shells
10)Give names of any two shells?
->
/bin/sh
/bin/bash
/bin/ksh
11)If we want to shift to sh shell,which command we have to use?
->$ sh
12)Which command is used to check the current shell ?
->echo $0
13)How to check the host name?
->$ hostname OR uname
14)Which command is used to check user and userinfo?
->$ cat /etc/passwd (uid , gid ,etc)
15)What is the id of the root user?
-> 0
16)In which range system users have their id?
-> 1-999
17)What is the id of ec2-user?
-> 1000
18)In which range normal users have their id?
-> Above 1000 (1001-1999)
The range in which group id exist?
Above 2000
19)Which command is used to print the present working directory?
->$ pwd
20)Which command is used to print the string?
->$ echo “string_name”
21)How to check the reboot time of the system?
->
$who -b ( shows reboot time)
$uptime -s ( show reboot time and date)
$last reboot ( show the history of the reboot)
22)How to change the date and time?
->$ sudo date -s 'Fri Apr 14 09:30:00 AM UTC 2002'
19)Which command is used to display the manual page of a command?
->$ man command_name
Example: $ man ls
20)Use of mandb
-> It is used to create or update the manual page database on the system.
21)The command in Linux is used to locate the executable file that will be
executed when a given command is run in the shell.
Shows the full path of the command.
->$which ls
22)The command that shows the directories that your shell will search through
when you entered a command
-> echo $PATH
***This two commands are same : echo $USER or whoami***
23)How to change the name, primary prompt, secondary prompt?
->
$PS1='Adhiraj'
$PS2='Sakshi @'
ec2-user@172.3.3.3 $
Adhiraj $ echo ‘ Hi ← PS1 (Adhiraj)
Sakshi @ hello ← PS2 (Sakshi @)
Sakshi @ hi’
24)How to create a user?Create one user
->
$sudo useradd username
Example: sudo useradd adhiraj
25)How to change the password of newly created user?Change the password of
adhiraj user
->
$sudo passwd username
Example: sudo passwd adhiraj
26)How to delete the user?
->$ sudo userdel username
Example: sudo userdel adhiraj
27)How to cleanly delete a user?
->$sudo userdel -r username
Example: sudo userdel -r adhiraj
28)How to create a hidden file?
->touch .file_name
29)In Linux, which file is the encrypted password file?
->sudo cat /etc/shadow
30)How to add a group?
->$sudo groupadd demo
31)If you want to create a group with a specific group ID then which command
have to be used?Also give example
->
$sudo groupadd -g group_id group_name
$sudo groupadd -g 1009 demo
32)How to change the group ID of existing group?Change the ID of demo group
which you have created earlier
->
$sudo groupmod -g new_ID groupname
$sudo groupmod -g 1111 demo
33)If we want to rename the group name,then how to do it?Change the name of
demo group which you have created earlier and rename it to test
->
$sudo groupmod -n new_name oldername
$sudo groupmod -n test demo
34)How to add a user in a group?Add a user name adhiraj to your test group
->
$sudo usermod - aG groupname username
$sudo usermod -aG test adhiraj
35)How to remove a user from group?Remove user adhiraj from test group
->$sudo gpasswd --delete username groupname
$sudo gpasswd --delete adhiraj test
36)How to delete a group?Delete group test
->$sudo groupdel test
37)Which command is used to list the contents in the current working directory?
->$ls
38)Which command is used to list the data according to time?
->$ls -lt
39)Which command is used to list the data according to time but in reverse order?
->$ls -ltr
40)How can we see the hidden files present in the directory?
Create a hidden file first and then display it
->
Create hidden file
$touch .hidden.txt
Display hidden file
$ls -a
41)How to list down the files created by a specific author?
->$ls --author
42)How to sort as well as list down all the contents in the current working
directory?
->$ls -s
43)How to list down the files of particular extension?List down all the files of txt
format
->$ls *.txt
44)How to change the directory?Suppose you have to change it to folder1
->$cd folder1
45)How to move to the home directory?
->$cd ~
46)How to change the current working directory to the root directory?
->$cd /
47)How to move to the previously used directory?
->$cd ..
48)How to open a file?
->$cat filename
49)Create a new file name new.txt using cat command and insert a data into it
->$cat > new.txt
An apple a day keeps the doctor away.
50)Now append data in new.txt file using cat command.
->$cat>>new.txt
I love apples.
51)How to add line numbers to non blank lines.
->$cat -b filename
52)How to add line numbers to blank as well as to non blank lines.
->$cat -n filename
53)Which command is used to sort a file?
->$sort file_name
54)How we can sort files f1.txt ,f2.txt, f3.txt
->$sort f1.txt f2.txt f3.txt
55)How to sort a file content in reverse order?
->$sort -r filename
56)How to sort a file without caring about case sensitivity?
->$sort -f filename
57)How to sort numerical data on the basis of their true value in maths?
->$sort -n filename
58)Suppose you have file named as data.txt and having content
apple,1020,aurangabad,Maharashtra
mango,422,washim,Gujarat
potato,85,pune,Goa
Sort the data according to third column
->$sort -t "," -k3 data.txt
59)Sort the data in data.txt according to second column
->$sort -t "," -k2 data.txt
60)Sort the data in data.txt according to the second column,but on the basis of
mathematical value.
->$sort -t "," -nk2 data.txt
61)Sort the data in data.txt according to the second column,but on the basis of
mathematical value but in reverse order.
->$sort -t "," -nrk2 data.txt
62)Sort the file and also print the no of occurence of elements.
->$sort filename | uniq -c
63)Sort the file and also show no duplicates and print the duplicate elements.
->$sort filename | uniq -cd
64)Sort the file and also show duplicate elements.
->$sort filename | uniq -d
*** Important
How to switch to command mode:
From Insert Mode: If you are in insert mode (where you can type and edit text),
press the Esc key. This will take you back to command mode.
From Visual Mode: If you are in visual mode (used for selecting text), press the Esc
key to exit visual mode and return to command mode.
From Replace Mode: If you are in replace mode, press the Esc key to exit replace
mode and return to command mode.
Once you are in command mode, you can use various navigation and editing
commands to manipulate text or save the file, as mentioned in the previous
response.
65)In vi mode, which symbol along with the colon is used to save the data?
-> :w
66)In vi mode which symbol along with colon is used to quit without saving the
data?
-> :q!
67)In vi mode which symbol along with colon is used to save the data and quit
from the file?
-> :wq
68)In vi mode which symbol along with colon is used to quit without saving the
data?
-> :q!
69)In vi mode, how can we go to the 10th line?
-> :10
70)In vi mode, how can we go to the last line?
-> :$
71)In vi mode ,if we want the numbering for each line for an example
hello ---> 1 hello
hii 2 hii
3
how are you 4 how are you
which command can be used?
->:set nu
72)Now we want to remove the numbering which we set in earlier question,then
which command can be used?
->:set nonu
73)How to search in a file opened using vi mode?
->/search_word
74)For example, let's say you have a file named example.txt with the following
contents:
This is an example text file
with some random words in it.
If you want to search for the word "example" in a case-insensitive manner, then
which command can be used?
->:set ic
/EXAMPLE
75)How to turn off case-insensitive search.
->:set noic
76)How to replace an existing word with a new word in vi mode?
->%s/existing_word/new_word
77)How to replace a existing word with new word in vi mode(Replace all
occurrence in each line)
->%s/existing_word/new_word/g
78)What is the difference between %s/existing_word/new_word and
%s/existing_word/new_word/g?
->
1. `%s/existing_word/new_word`: This is a basic search and replace operation
that replaces the first occurrence of "existing_word" with "new_word" in a given
text or string. It's typically used with tools or functions that support basic text
replacement. If multiple instances of "existing_word" exist in the text, only the
first occurrence is replaced.
2. `%s/existing_word/new_word/g`: The addition of the "g" at the end of the
expression stands for "global." When used with search and replace functions or
regular expressions, this will replace all occurrences of "existing_word" with
"new_word" in the given text. It doesn't stop after the first occurrence; it
continues searching and replacing until it reaches the end of the text or string.
Here's a simple example to illustrate the difference:
Suppose you have the text: "apple orange apple banana apple" and you want to
replace "apple" with "fruit."
- Using `%s/apple/fruit`, you'll get: "fruit orange apple banana apple" (only the
first "apple" is replaced).
- Using `%s/apple/fruit/g`, you'll get: "fruit orange fruit banana fruit" (all
occurrences of "apple" are replaced).
The "g" modifier makes the replacement operation global, affecting all instances
of the search term in the text.
79)Write a command to replace a word madhu with lalita (Replace all occurrences
within 20 and 30th line)
->20,30s/madhu/lalita
80)Command mode (Movement of cursor around the file) "h" is used for
->Move one char left side
81)Command mode (Movement of cursor around the file) "j" is used for
->Move one line down
82)Command mode (Movement of cursor around the file) "k" is used for
->Move one line up
83)Command mode (Movement of cursor around the file) "l" is used for
->Move one char right side
84)Command mode (Movement of cursor around the file) "w" is used for
->Move one word in forward direction
85)Command mode (Movement of cursor around the file) "b" is used for
->Move one word in backward direction
86)Command mode (Movement of cursor around the file) "$" is used for
->Move to the last char of the lineCommand mode
87)Command mode (Movement of cursor around the file) "^" is used for
->Move to the begining char of the current line
88)Command mode (Movement of cursor around the file) "0" is used for
->Move to the very begining of the current line
89)Command mode (Movement of cursor around the file) "G" is used for
->Move to the last line of the file
90)Command mode (Movement of cursor around the file) "gg" is used for
->Move to the first line of the file
91)Write a command to move 5th char left side
->5h
92)Write a command to move 6 line down
->6j
93)Write a command to move 3 line up
->3k
94)Write a command to move 4 char right side
->4l
95)Write a command to move 5 word in forward direction
->5w
96)Write a command to move 8 word in backward direction
->8b
97)Which char is used to copy
->y
98)Which char is used to paste
->p
99)Which char is used to delete
->d
100)How to search a word in command mode
->/word
101)If we want to search a word in command mode in forward direction then
which char we have to press?
->n
102)If we want to search a word in command mode in backward direction then
which char we have to press?
->N
103)List down all the insert modes commands
->i I a A o O s S
104)The command which is used to check whether there is any modification in
the file or not?
->$md5sum filename
105)Which command is used to split the file?
->$split filename
106)Write a command to split a file on the basic of no of lines.Split the file try.txt
and each file should contain 4 lines
->$split -no_of_line filename
$split -4 try.txt
107)Write a command to split a file on the basic of bytes.Split the file try.txt and
each file should contain 426723 byte
->split -b byte_value filename
split -b 426723 try.txt
108)Write a command to split a file on the basis of no of chunks.Split the file
try.txt into 3 files.
->$split -n no_of_files filename
$split -n 3 try.txt
109)Which command is used to set default permissions for files or directories
that are created by the user?
->$umask
110)Which command is used to translate the characters?
->$ tr
111) Write a command to convert all the vowels which are in small letters to
capital letters in the given sentence and print that newly translated sentence.
"Man is Mortal"
->$echo "Man is Mortal" |tr 'aeiou' 'AEIOU'
112)Write a command to convert 'abcd' '!@*%' in the given sentence.
"I love apples,dogs,cat and banana".
->$echo "I love apples,dog,cat and banana" |tr 'abcd' '!@*%'
113)Write a command if we want to delete a specific character from the string
using tr command.
"Man is Mortal"
Delete all the vowels .
->$echo "Man is Mortal" |tr -d 'aeiou'
114)Write a command to delete all the vowels from fruits.txt file using .
->$cat fruits.txt | tr -d 'aeiou'
115)Write a command to squeeze all 'o'to single o
"Helloooo Brooooo"
->$echo "Helloooo Brooooo" |tr -s 'o' 'o'
116)Write a command to squeeze 'lo' 'lo'
"Hellllloooooooooo Brrroooooo"
->$echo "Hellllloooooooooo Brrroooooo" |tr -s 'lo' 'lo'
117)Write a command to change space -> tab
"Hello my name is sakshi"
->$echo "Hello my name is sakshi" | tr ' ' '\t'
118)Write a command to print each word in new line
"Hello my name is sakshi sawalikar"
->$echo "Hello my name is sakshi" | tr ' ' '\n'
119)How to find files in a directory using the whole path. Path=
/home/ec2-user/folder1 and filename that you have to search is f1.txt
->$find full_path -name 'filename'
$find /home/ec2-user/folder1 -name 'filename'
120)How to get the last 10 lines of a file.Display last 10 lines of file try.txt
->tail try.txt
121)How to get the last 3 lines of a file.Display last 3 lines of file try.txt
->tail -n 3 try.txt
122)How to get first 10 lines of a file.Display the first 10 lines of file try.txt
->head try.txt
123)How to get the first 5 lines of file.Display the first 5 lines of file try.txt
->head -n 5 try.txt
1000 lines
Print 501-510
-> head -n 510 | tail -n 10 f1.txt
124)Sort the each word of a file try.txt
->cat try.txt | tr -s ' ' '/n' | sort
125)Sort the file try.txt according to the occurrence (count) of each word in the
file and then display the word having the highest count and comes last after
sorting .
->cat try.txt | tr -s ' ' '/n' | sort |uniq -c |sort -n |tail -n 1
126)Sort the file try.txt according to the occurrence (count) of each word in the
file and then display the first word having the highest count and comes first after
sorting .
->cat try.txt | tr -s ' ' '/n' | sort |uniq -c |sort -n |head -n 1
127)Which command is used in linux to view the content of text file one page at a
time.Use that command to view the file f5.txt
->$more f5.txt
128)Write a command to search a word (pavbhaji)in a text file named try.txt using
less command.
->$less try.txt
/pavbhaji
129)Suppose we have a txt file named as f1 having data
A B C D ------------M N O
And we want to print the data in the middle(E F G H) then write a command for
this task.
->$head -n 8 f1.txt|tail -n 4
130)Suppose we have f2.txt having 10000 records and we want from 500 to 510
then
->$head -n 510 f2.txt | tail -n 11
131)Write a command to copy 5000 lines from f2.txt into f3.txt
->$head -n 5000 f2.txt > f3.txt
132)Write a command to see no of lines ,word count and characters of file try.txt
->$wc try.txt
133)If we want to see numbers of lines only ,then write a command for it.
->$wc -l try.txt
134)If we want to see numbers of word count only ,then write a command for it.
->$wc -w try.txt
135)If we want to see numbers of no of characters only ,then write a command for
it.
->$wc -c try.txt
136)Write a command to extract specific fields from emp.txt having data
FPT1,ADHI, SCIENCE
MPT2,SAKSHI,MATHS
HPT3,SHRUTI,BCOM
Write a command to get the output as
FPT1,
MPT2,
HPT3,
->$cut -c 1-5 emp.txt
137)Write a command to get the output as
FPT1
MPT2
HPT3
->$cut -c 1-4 emp.txt
138)Write a command to extract specific fields from emp.txt having data and
write that extracted data into another txt file.
Write a command to get the output as
FPT1,
MPT2,
HPT3,
and save it into another file named as f1.txt
->$cat emp.txt | cut -c 1-5 > f1.txt
139)Write a command to extract 2-5 fields from emp.txt having data and write
that extracted data into another txt file named as f1.txt
->$cat emp.txt |cut -c 2-5 >f1.txt
140)Write a command to extract 3-10 fields from emp.txt having data and write
that extracted data into another txt file named as f1.txt
->$cat emp.txt |cut -c 3-10 >f1.txt
141)Write a command to display the content of files f1.txt f2.txt f3.txt vertically
using paste command
->$paste f1.txt f2.txt f3.txt
142)Write a command to display following output using cut command for emp.txt
file
Output:-FPT1
MPT2
HPT3
->cut -d "," -f2 emp.txt
143)Write a command to display the following output using cut command for
emp.txt file to display third column.
->$cut -d "," -f3 emp.txt
144)Write a command to redirect the output of date command save the output in
m2.txt
->$date > m2.txt or date 1>m.txt
145)Write a command to redirect the output of a command save the error in
m2.txt
->$dates 2>m2.txt
146)Write a command to see the processes that are currently active.
->$ps
147)Print the shell name where processes are currently running.
->$echo $0
148)Write a command to print process id
->$echo $$
149)How to check in which terminal we are?
->$tty -> /dev/pts/
150)Which command is used in Linux to display a detailed list of currently
running processes in a full format.
->$ps -f
$ ps -e … who the demon process / all process
151)Which command in Linux is a real-time process monitoring tool that
provides a dynamic overview of the system's current resource usage, including
CPU, memory, and other system statistics.
->$top
152)What is the use of -e? Also give one example.
->If we want to print a word or line in new line than we can use -e
Example:- $echo -e "Hello\nWorld"
153)Write a program which will create a beep sound.
->$echo -e "Hello\a\a\a\aworld"
154)Write a command to change the colour(Make it Red) of word sakshi
->echo -e "\e[1;31m sakshi\e[0m "
155)Write a process to create and execute a script .
->Step1:=$vi sleep.sh
Step2:= Press i
Step3:=Write a code
#!/bin/bash
echo "a"
sleep 1
echo "b"
sleep 1
echo "c"
sleep 1
echo "d"
sleep 1
echo "e"
sleep 1
echo "d"
sleep 1
echo "e"
sleep 1
echo "f"
sleep 1
echo "g"
sleep 1
echo "h"
sleep 1
echo "i"
sleep 1
echo "j"
Step4:=Press :wq
Then hit enter
Step5:=./sleep.sh
156)How to terminate the currently executing process.
->$ctrl+c
157)How to pause the currently executing process.
->$ctrl+z
158)How to start the paused process again.
->$fg
159)How to start the paused process again but in the background.
->$bg
160)Which command is used to monitor the contents of a file in real-time,
particularly log files, by displaying the last few lines of the file and
continuously updating the display as new lines are added to the file.
->$tail -f filename
161)Which command is used to list the available signal names or numbers on a
Unix-like system.
->$kill -l
1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP
6) SIGABRT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1
11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM15) SIGTERM
16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP
162)Which command is used to display detailed information about processes
running on a Unix-like system. It provides a full listing of processes in
a "long" format, showing information such as the process ID (PID), parent proce
(PPID), CPU and memory usage, start time, and command
associated with each process.
->ps -f
163)Alternate to(ctrl+z) stop the currently executing process.
->$kill -19 PID_NUMBER
164)Alternate to(fg and bg) to resume the currently executing process.
->$kill -18 PID_NUMBER
165)Alternate to(ctrl+c) terminate the currently executing process.
->$kill -9 PID_NUMBER
166)Which command used in Unix-like operating systems to run a command or
script that will continue running even after the user logs out or
terminates the session. It stands for "no hangup."Give one example
->Step 1:- vi sleep2.sh
Step2:-#!/bin/bash
>number.txt
for N in {1..1000}
do
echo ${N}>>numbers.txt
echo Hello$N
sleep 1
done
Step3:-chmod u+x sleep2.sh
Step4:-nohup ./sleep2.sh &
167)How to kill the process?Kill sleep2.sh
->pkill -f sleep2.sh
168)Which command is used to display RAM status.
->$free
169)Which command is used to display disk space usage (disk free)
->$df or $df -h
170)Which command is used in Unix-like operating systems to estimate file and
directory disk usage. Which provides information about the space
occupied by files and directories, helping you analyse disk usage on your system.
->$du -h (disk usage)
171)Declare a variable BASIC,DA,TA,HRA,GROSS assign BASIC as 7000 and find
the GROSS salary also display it on terminal.
->#!/bin/bash
BASIC=70000
DA=`echo ${BASIC} \*.1 | bc`
TA=`echo ${BASIC} \*.1 | bc`
HRA=`echo ${BASIC} \*.1 | bc`
GROSS=`echo ${BASIC} + ${DA} + ${TA} + ${HRA} | bc
echo The Gross Salary is ${GROSS}
172)Write a script using the read command.
->#!/bin/bash
read -p "Enter you salary" SAL
echo "Your salary is:"${SAL}
173)Which command is used to start debugging mode.
->$set -x
174)Which command is used in debugging mode.
->$set +x
175)Which command is used to list the cron jobs for the current user,which is a
time-based job scheduler in Unix-like operating systems, and each
user can have their own set of scheduled tasks or jobs.
->$crontab -l
176)Which command is used to edit the crontab command
->$crontab -e
177)Write an example of how to use the crontab command to create and edit cron
jobs.
->Step1:-To edit the cron jobs for the current user, use the following command:
$crontab -e
Step2:-The general format of a cron job line is as follows:
$* * * * * command or $* * * * */path/to/command
For example, to schedule a command to run every day at 9:30 AM, you can add the
following line:
$30 9 * * * /home/ec2-userW/to/command
Step3:-To view the updated list of cron jobs, you can use the crontab -l command:
$crontab -l
178)Write a script to hide password while writing
->#!/bin/bash
read -p "Enter name:" UNAME
read -sp "Enter password:" PASSWARD
179)Example of command line argument
->Step1:- vi ex2.sh
Step2:-#!/bin/bash
# Access the first command-line argument
name=$1
# Display a greeting message
echo "Hello, $name! Welcome to Linux."
Step3:-./ex2.sh sakshi
180)Write a program to concatenate two strings.
->Step1:-vi ex3.sh
Step2:-#!/bin/bash
# Access the first command-line argument
name=$1
surname=$2
# Display a greeting message
echo "Hello," $name $surname" ! Welcome to Linux."
Step3:-./vi ex3.sh sakshi sawalikar..
181)Use expr to add two whole numbers.
->$expr 20+30 | bc
182)Use expr to add two decimal numbers
->expr 20.5+20.5 | bc
183)Use bc two add two whole numbers
->echo 20+24 | bc
184)Use bc two add 20.5 and 74
->echo 20.5+74 | bc
185)Write a command to convert decimal to binary.
->echo "ibase=10;obase=2;47" | bc
186)Write a command to convert decimal to octal.
->echo "ibase=10;obase=8;47" |bc
187)Write a command to convert decimal to hexadecimal.
->echo "ibase=10;obase=16;47" | bc
188)Write a command to compress a file.
->$gzip filename
189)Write a command to decompress a file
->$gzip -d filename.gz
190)How to tar and untar a file.
-> tar a file: $ tar -cvf archive.tar /path/to/your/file
untar a file: $ tar -xvf archive.tar
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