Linux/Unix Commands

Unix/Linux MCA-IV
N i k i t a K e s h a r w a n i Page 1
Utility Commands:-
1. date: - Date sets a system's date and time.
Syntax: - $ date [OPTION]… [+format]… [ENTER]
Format:
Option Description
%d Day of Month (e.g.01)
%m Month (01..12)
%y Last two digits of year(00..99)
%H Hour(00..23)
%M Minute (00..59)
%S Second (00..60)
%T Time; same as %H/%M/%S.
%D Date; same as %m/%d/%y
%h The abbreviated month name (e.g. Jan)
Example:

Unix/Linux MCA-IV
2. cal :- Shows the calendar.
Syntax:- $ cal [OPTION] …[ENTER]
Example:
3. type: - It locates the file in the directory.
Syntax: - $ type [FILENAME]… [ENTER]
Example:

Unix/Linux MCA-IV
4. echo: - Display a line of Text.
Syntax: - $ echo [arg...]… [ENTER]
Example:
5. man: - For showing the manual page of any command.
Syntax: - $ man [name..]… [ENTER]
Example:

Unix/Linux MCA-IV
6. whatis: -Display one line manual page description.
Syntax:- $ whatis [name]… [ENTER]
Example:
7. printf: - Format and print data.
Syntax: - printf(const char *format, ...);
Formats: Controls the output as in c printf.
Option Description
%s String
%d Decimal
%o Octal
%x Hexadecimal
%f Floating point
n New line
t Horizontal tab
v Vertical tab
Example:

Unix/Linux MCA-IV
8. pwd: - pwd (Present Working Directory) prints the name of current/working
directory.
Syntax:- $ pwd… [ENTER]
Example:
Directory Command
9. mkdir: - (Make Directory) It is used to create a new directory.
Syntax: - $ mkdir [OPTION]…Directory… [ENTER]
Options:
Option Description
-m (mode) set file mode (as in chmod)
-p (parent) no error if existing, make parent directories as needed
-v (verbose) print a message for each created directory
Example:

Unix/Linux MCA-IV
10. cd: - To change directory - change the current working directory to a specific Folder.
Syntax:- $ cd [filename] or [path]… [ENTER]
$ cd [OPTION]…Directory … [ENTER]

Unix/Linux MCA-IV
Example:
11. rmdir: - remove empty directories
Syntax: - $ rmdir [OPTION]... DIRECTORY… [ENTER]
Options:
Option Description
-p (parent) remove DIRECTORY and its ancestors; e.g., 'rmdir -p a/b/c' is
similar to 'rmdir a/b/c a/b a'
-v (verbose) print a message for each directory processed
Example:

Unix/Linux MCA-IV
12. ls: - List directory Contents.
Syntax: - $ ls [OPTION]…[FILE]…[ENTER]
Option:
Option Description
-a Do not ignore entries starting with.
-l use a long listing format
-t sort by modification time
-lat Same as -l-a-t
-i print the index number of each file
-R list subdirectories recursively
-s print the allocated size of each file, in blocks
-S sort by file size
-d list directory entries instead of contents, and do not dereference symbolic links
-m fill width with a comma separated list of entries
Example:

Unix/Linux MCA-IV

Unix/Linux MCA-IV
File Command
13. cat: - concatenate files and print on the standard output.
Syntax: - $ cat [OPTION]… [FILE]… [ENTER]
Option:
Option Description
-n number all output lines
-b number nonempty output lines, overrides –n
-T display TAB characters as ^I
-E display $ at end of each line
Example:

Unix/Linux MCA-IV
14. cp: -copy files and directories
Syntax: - $ cp [OPTION]... SOURCE... DIRECTORY… [ENTER]
Option:
Option Description
-i prompt before overwrite
-R copy directories recursively
-l hard link files instead of copying
-v Explain what is being done.

Unix/Linux MCA-IV
Example:

Unix/Linux MCA-IV
15. rm: - (Remove) remove files or directories.
Syntax: - $ rm [OPTION]... [FILE]... [ENTER]
Option:
Option Description
-i Prompt before every removal.
-R Remove directories and their contents recursively.
-v Explain what is being done.

Unix/Linux MCA-IV
Example:
16. mv: - move (rename) files.
Syntax: - $ mv [OPTION]... SOURCE... DIRECTORY… [ENTER]
Option:
Option Description
-i prompt before overwrite
-n do not overwrite an existing file
-f do not prompt before overwriting
-v explain what is being done
Example:

Unix/Linux MCA-IV
17. touch: -change file timestamps.
Syntax:- $ touch [OPTION]... FILE... [ENTER]
Example:
18. file: - Determine file type.
Syntax: -$ wc [OPTION]... [FILE]... [ENTER]
Example:

Unix/Linux MCA-IV
19. wc: - print newline, word, and byte counts for each file .
Syntax:- $ wc [OPTION]... [FILE]... [ENTER]
Option:
-c print the byte counts
-m print the character counts
-l print the newline counts
-L print the maximum display width
-w print the word counts
Example:

Unix/Linux MCA-IV
20. chmod: - change file mode bits.
Syntax: -$ chmod [OPTION]... MODE [, MODE]... FILE... [ENTER]
Where each MODE is of the form [ugoa...][[-+=][rwx...]...]
U User
G Group
O Others
A All
R Read
W Write
X Execute
+ Causes the selected file mode bits to be added to the existing file mode
- Causes the selected file mode bits to be removed to the existing file mode
= Causes the selected file mode bits to be added to the existing file mode.
Example:

Unix/Linux MCA-IV

Unix/Linux MCA-IV
Input-Output Redirection
21. Output Redirection: - Denoted by > .
> (Truncate)
>> (Append)
Syntax: - $ command > Filename… [ENTER]
$ command >> Filename… [ENTER]
Example:
22. Input Redirection: - Denoted by < .
Syntax: - $ command < filename… [ENTER]
Here, File is considered as Standard input.
Example:
23. Error Redirection: - Output channel for error messages is standard error.
Default destination is user’s screen.
Syntax: - $ command > filename… [ENTER]
Example:

Unix/Linux MCA-IV
Read Statement
24. read: - Used to taking one or more input from user or read from a file descriptor.
Syntax: - $ read varname… [ENTER]
To unset the variable:
$ unset varname… [ENTER]
Example:
Expression Statement
25. expr: - evaluate expressions.
Syntax: - $ expr EXPRESSION… [ENTER]
$ expr OPTION… [ENTER]
EXPRESSION may be:

Unix/Linux MCA-IV
Expression Description
ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2
ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0
ARG1 < ARG2 ARG1 is less than ARG2
ARG1 <= ARG2 ARG1 is less than or equal to ARG2
ARG1 = ARG2 ARG1 is equal to ARG2
ARG1 != ARG2 ARG1 is unequal to ARG2
ARG1 >= ARG2 ARG1 is greater than or equal to ARG2
ARG1 > ARG2 ARG1 is greater than ARG2
ARG1 + ARG2 Arithmetic sum of ARG1 and ARG2
ARG1 - ARG2 Arithmetic difference of ARG1 and ARG2
ARG1 * ARG2 Arithmetic product of ARG1 and ARG2
ARG1 / ARG2 Arithmetic quotient of ARG1 divided by ARG2
ARG1 % ARG2 Arithmetic remainder of ARG1 divided by ARG2
length STRING Length of STRING.
Example:
26. test: - check file types and compare values.
Syntax: -$ test EXPRESSION... [ENTER]
EXPRESSION may be:
Expression Description
INTEGER1 -eq INTEGER2 INTEGER1 is equal to INTEGER2
INTEGER1 -gt INTEGER2 INTEGER1 is greater than INTEGER2
INTEGER1 -le INTEGER2 INTEGER1 is less than or equal to INTEGER2
INTEGER1 -lt INTEGER2 INTEGER1 is less than INTEGER2

Unix/Linux MCA-IV
INTEGER1 -ne INTEGER2 INTEGER1 is not equal to INTEGER2
STRING1 = STRING2 the strings are equal
STRING1 != STRING2 the strings are not equal
-n STRING the length of STRING is nonzero
-z STRING the length of STRING is zero
STRING1 = STRING2 the strings are equal
STRING1 != STRING2 the strings are not equal
Example:

Unix/Linux MCA-IV
Environment Variable
27. PATH: - Display list directories.
Syntax: - $ echo $PATH… [ENTER]
28. HOME: - Users home directory to store files.
Syntax: - $ echo $HOME… [ENTER]
29. PS1: - Display shell prompt in the bourne shell and variant.
Syntax:- $ echo $PS … [ENTER]
30. TEMP: - Path to where process can store files.
Syntax: - $ echo $TEMP… [ENTER]
31. JAVA_HOME: - JDK path.
Syntax: - $ echo $JAVA_HOME… [ENTER]
32. ORACLE_HOME: - Oracle data base installation path.
Syntax: - $ echo $ORACLE_HOME… [ENTER]
33. TZ: - Setting time zone.
Syntax: - $ echo $TZ… [ENTER]
34. USER: - Current logged in user name.
Syntax: - $echo $USER… [ENTER]

Unix/Linux MCA-IV
35. SHELL: - The current shell.
Syntax: - $ echo $SHELL… [ENTER]
36. OSTYPE: - Type of operating system.
Syntax: - $ echo $OSTYPE… [ENTER]
37. PWD: - Path to present working directory.
Syntax: - $ echo $PWD… [ENTER]
38. HISTFILE: - The name of file in which command history is saved.
Syntax: - $ echo $HISTFILE… [ENTER]
39. export: - To change the environment variable value.
Syntax: - $ export PS1 = VALUE … [ENTER]
Example:

Unix/Linux MCA-IV
40. Command Line Arguments: - The command-line arguments $1, $2, $3, ...$9
are positional parameters, with $0 pointing to the actual command, program, shell
script, or function and $1, $2, $3, ...$9 as the arguments to the command.
Example:

Unix/Linux MCA-IV
Output:
Filter Commands:-
41. Grep: - Print lines matching a pattern.
Syntax:- $ grep [OPTIONS] PATTERN [FILE...]… [ENTER]
Options:
Options Description
--color Display matches in color.
-i Matches either upper or lowercase.
-n Prints the matched line and its line number.
-v Prints all lines that do not match pattern.
-l Prints only the names of files with matching lines.
-L Prints the name of files without match.
-c Prints only the count of matching lines.
-o Display only matched portion not whole matched line.
-b Print the 0-based byte offset within the input file before each line of output.
-f Obtain patterns from FILE, one per line.
Example:

Unix/Linux MCA-IV

Unix/Linux MCA-IV
42. Sed: - Stream editor for filtering and transforming the text.
Syntax: - sed [OPTION]... {Script} [Input-file]... [ENTER]
Option:
Options Description
P Prints the line.
D Deletes the line.
s/pattern1/pattern2/ Substitutes the first occurrence of pattern1 with pattern2
$ Matches the end of lines
-e add the script to the commands to be executed
-n suppress automatic printing of pattern space
G Give one line space between each line.
G;G Two new lines between each line.

Unix/Linux MCA-IV
'2,5!d' This deletes everything except starting from 2nd till 5th line
'4,10p' Lines starting from 4th till 10th are printed
Example:

Unix/Linux MCA-IV

Unix/Linux MCA-IV
43. head: - output the first part of files.
Syntax: - head [OPTION]... [FILE]... [ENTER]
Option:
Options Description
-n, --lines=[-]NUM Print the first NUM lines.
-c, --bytes=[-]NUM Print the first NUM bytes of each file.
Example:

Unix/Linux MCA-IV
44. tail: - output the last part of files.
Syntax: - tail [OPTION]... [FILE]... [ENTER]
Option:
Option Description
-n, --lines=[-]NUM Print the last NUM lines of each file.
-c, --bytes=[-]NUM Print the first NUM bytes of each file.
Example:

Unix/Linux MCA-IV
45. Pipe: - connect two commands together so that the output from one program
becomes the input of the next program. To make a pipe put a vertical bar ( | ) on the
command line between two commands.
Syntax: - $ command | command … [ENTER]
Example:
46. tee:- Read from standard input and writes to standard output or files.
Syntax: - $ tee [OPTION]… [FILE]… [ENTER]
Option:
Option Description
-a Append to the given files, do not overwrite.
-i Ignore interrupt Signals.

Unix/Linux MCA-IV
Example:
47. Command Substitutions: - Used to assign the output of a command to a variable.
Syntax: $ varName=`command`… [ENTER]
Example:

Unix/Linux MCA-IV
48. Command History: - To display a list of previously entered commands.
Syntax: - $ history… [ENTER]
 To finding the location of history file in your system.
$ echo $HISTFILE
 To show the default history size.
$ echo $HISTSIZE… [ENTER]
 To display only the most recent command.
$ history [n]… [ENTER]
Example:
49. Clobbering:-
 Will prevent > from clobbering by making it issue an error message instead.
Syntax: - $ set –o noclobber… [ENTER]
 Use >| operator to force the file to be overwritten
$ command >| FILENAME… [ENTER]
 To turnoff noclobber
$ set +o noclobber… [ENTER]

Unix/Linux MCA-IV
Example:
50. noglob:- It disables wild card characters *,?,[,],~ in user shell.
Syntax: -
 To stop wild card characters permanently:
$ set -o noglob… [ENTER]
 To unset the noglob:
$ set +o noglob… [ENTER]
51. pushd and popd: -
Syntax: -
 For pushd:
$ pushd [DIRECTORY PATH]… [ENTER]
 For popd:
$ popd… [ENTER]

Unix/Linux MCA-IV
Example:
52. Process Priority:-
 Checking the priority of running process.
$ top.. [ENTER]
Or
$ ps –eo [FIELDS/COLUMNS]
FIELDS/COLUMNS:
PID Process Id.
USER User Name.
PR Priority
NI Nice value.
VIRT Virtual memory Size.
RES Resident Memory size(KiB)
SHR Shared memory size.
S Process status.
%CPU CPU usage.
%MEM Memory usage.
TIME+ CPU Time. Hundredths

Unix/Linux MCA-IV
Command Command name or command line.
Example:
To set the priority on new process:
$ nice –n [NICE VALUE][COMMAND]… [ENTER]
To setting priority on existing process:
$ renice [nice value] –p [process id]… [ENTER]

Unix/Linux MCA-IV
SHELL SCRIPTING
1. Write a shell script for addition, subtraction, multiplication, division, modulo
division?
Program:
Output:

Unix/Linux MCA-IV
2. Write a Linux shell script to check the given year is leap year?
Program:
Output:

Unix/Linux MCA-IV
3. Write a Linux shell script to check given number is prime or not?
Program:
Output:

Unix/Linux MCA-IV
4. Write a Linux shell script for Fibonacci series?
Program:
Output:

Unix/Linux MCA-IV
5. Write a Linux shell script to calculate factorial of given number?
Program:
Output:

Unix/Linux MCA-IV
6. Write a Linux shell script for Armstrong number?
Program:
Output:

Unix/Linux MCA-IV
7. Write a Linux shell script to check largest no of three numbers?
Program:
Output:

Unix/Linux MCA-IV
8. Write a shell script to see date, time, username, current directory?
Program:
Output:

Unix/Linux MCA-IV
9. Write a Linux shell script to swapping variable?
Program:
Output:

Unix/Linux MCA-IV
10. Write a Linux shell script to check given no odd or even?
Program:
Output:

Unix/Linux MCA-IV
11. Write shell script to find multiplication table using for loop?
Program:
Output:

Unix/Linux MCA-IV
12. Write a Linux shell script to print employee payroll (basic, DA, HRA, PF, Gross
salary, Net Salary)?
Program:
Output:

Unix/Linux MCA-IV
13. Write a Linux shell script to perform all arithmetic operation using command
line argument?
Program:
Output:

Unix/Linux MCA-IV
14. Write a shell script to accept character and check for following?
 If user enter character (A-Z) then show upper case letter.
 If user enter character (a-z) then show lower case letter.
 If user enters digital no (0-9) then show digital number.
 *, $, #, @ show its special character.
Program:
Output:

Unix/Linux MCA-IV
15. Write a Linux shell script show various system configurations?
 Currently log user and His/her login name.
 Your current shell.
 Your current directory.
 Your operating system type.
 Show mouse setting.
 Show keyboard
 Show network setting.
 Show Path
 currently logged number of users
Program:

Unix/Linux MCA-IV
Output:

Unix/Linux MCA-IV
16. Write a shell script to check given name is a file or a directory or special file or
not?
Program:
Output:

Unix/Linux MCA-IV
17. Write a shell script to determine whether given file exist or not, existing file
name supplied by command line argument also check for sufficient no of
command line argument?
Program:
Output:

Unix/Linux MCA-IV
18. Write shell script to copy the content is one file to another file?
Program:
Output:

Unix/Linux MCA-IV
19. Write a shell script to print addition of given of all digits?
Program:
Output:

Unix/Linux MCA-IV
20. Write a shell script to search element present in list or not. (Binary & Linear
Search).
Program: Binary Search

Unix/Linux MCA-IV
Output:
Linear Search

Unix/Linux MCA-IV
Output:

Unix/Linux MCA-IV
21. Write a shell script for bubble & selection sort.
Program: Bubble sort
Output:

Unix/Linux MCA-IV
Selection Sort:

Unix/Linux MCA-IV
Output:

Unix/Linux MCA-IV
22. Write a Linux shell script to sort the given no in ascending or descending orders?
Program:

Unix/Linux MCA-IV
Output:

Unix/Linux MCA-IV
23. Write a Linux shell script to implement read, write and execute permission?
Program:
Output:

Unix/Linux MCA-IV
24. Write a Linux shell script to print the following pattern?
1
2 2
3 3 3
4 4 4 4
5 5 5 5 5
Program:
Output:

Unix/Linux MCA-IV
25. Write a Linux script to print the following pattern using for loop?
*
* *
* * *
* * * *
* * * * *
* * * *
* * *
* *
*
Program:
Output:

Unix/Linux MCA-IV
26. Write a Linux shell script to implement break & continue statement?
Program:
Output:

Unix/Linux MCA-IV
27. Write a Linux shell script to calculate area of circle & rectangle?
Program:
Output:

Unix/Linux MCA-IV
28. Write a Linux shell script to count no of file in directory?
Program:
Output:

Unix/Linux MCA-IV
29. Write a shell script to generate all combination of 1, 2 and 3.
Program:
Output:

Unix/Linux MCA-IV
30. Write a shell script to check given string or number is palindrome or not?
Program: Number
Output:

Unix/Linux MCA-IV
String:
Output:

Unix/Linux MCA-IV
31. Write a Linux shell script to implement create () system calls?
Program:
Output:

Unix/Linux MCA-IV
32. Write a Linux shell script to implement Open () system calls?
Program:
Output:

Unix/Linux MCA-IV
33. Write a Linux shell script to implement Open (), read (), write () system calls?
Program:
Output:

Unix/Linux MCA-IV
34. Write a shell script which receives two file names as argument. It checks
whether two file contents are same or not. If they are same then second file is
deleted.
Program:
Output:

Unix/Linux MCA-IV
35. Write a shell script for decimal to binary conversion?
Program:
Output:

Unix/Linux MCA-IV
36. Execute any 5 file handling commands with required options on the terminal.
1) Displaying the file: - Displays the file on standard output.
Syntax: - $ cat filename… [ENTER]
Example:
Concatenates the first two files and places the result on the third, overwriting the current
contents of file3.
Syntax: - $ cat file1 file2 > file3.. [ENTER]
Example:
2) Copying File: - copy files and directories
Syntax: - $ cp [OPTION]... SOURCE... DIRECTORY… [ENTER]

Unix/Linux MCA-IV
Example:
3) Moving a File: - Move file command (which essentially renames a file) is mv .
Syntax: - $ mv [OPTION]... SOURCE... DIRECTORY… [ENTER]
Example:
4) Deleting a File: - Remove files.
Syntax: - $ rm [OPTION]... [FILE]... [ENTER]

Unix/Linux MCA-IV
Example:
5) Searching: - searches the files for a pattern specified by a limited regular
expression.
Syntax: - $ grep [OPTIONS] PATTERN [FILE...]… [ENTER]
Example:

Unix/Linux MCA-IV
37. Create an awk program to calculate to check even or odd number.
Program:
Output:

Unix/Linux MCA-IV
38. Create an awk program to calculate gross salary from employee database file.
Program:
Output:

Unix/Linux MCA-IV
39. Create an awk program to provide an increment of 10%on the salary on the employee
database file containing 'salary' field.
Program:
Output:

Unix/Linux MCA-IV
40. Create sed script file to make following replacement on student database file:
 Name- John as Joney
 Rollno- 101 as 110
 Percentage- 97 as 78
 Address- Raipur as Durg
Program:
Output:

Unix/Linux MCA-IV
41. Create a sed script file to perform following operation on student database:
 Insertion.
 Append
 Deletion
Program:

Unix/Linux MCA-IV
Output:

Unix/Linux MCA-IV
42. Write a linux shell script to implement system call that will check for disk
appearance of child and exit return its p_id , modify its various used and keep
child process.
Program:

Unix/Linux MCA-IV
Output:

Unix/Linux MCA-IV
43. Write a linux shell script to implement system call signal () pass one argument
that will contain signal () and if it is valid then display signal flag otherwise error
will be generated.
Program:
Output:

Linux/Unix Commands

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