BSR Technologies: Unix Basic Commands with examples part 1

Command	Description
1. logname	Current user name
2. pwd	Present working directory
3. uname	Display kernel name
4. uname -n	Print network hostname
5. uname -r	Display kernel version
6. uname -v	Display kernel release date
7. uname -i	Print hardware platform
8. uname -o	Print the operating system
9. uname -p	Print the processser name
10. uname -a	Print all information
11. date	Display system date and time
12. clear	To clear the screen
13. cal	Display current month calendar
14. cal 2014	Display 2014 calendar
15. cal 9 1987	Displays the September 1987 calendar
16. bc	Open calculator
17. bc -v	Version of calculator
18. hostname	Display server name
19. hostname -i	Display server IP address
20. tty	Display terminal name
21. who	To display how many users connected to server
22. whoami	Display current username
23. uptime	Display how long server is “up &running”, no. Of users connected &avg load on the server.
24. which <command name>	Show the full path of command
25. whereis <command name>	Display the binary, source, and manual page files for a command
26. find	Search for files in a directory hierarchy

27. set system date and time

# date -s “yyyy-mm-dd hh:mm:ss”

28. To view help for a command (manual pages)

# man <command>

29. Viewing list of Files & Directories:

Syntax : # ls <options> <file>

Options:

-a --> To check the hidden object

-l --> To list the properties of an object

-s --> To check the size in block

-r --> To check reverse order

-R --> List Sub directories Recursively

-Q --> To see files in double quotes

-m --> List of entries with comma separated

Eg :-

# ls -a

# ls -la

# ls -lr

Working with Files:-

A collection of data is called file. In linux – platform, CAT, Touch, vi are some at the default commands. To create a file, but there are some differences between these three commands.

30. Cat (concatenation):

This command is used to create single file with data and also to check the data of exiting file, but we cannot modify the data.

Create a file :

# cat > file

-------------

ctrl+d (save & quit)

31. Open the file:

# cat < filename

# cat filename

32. To append the file:

# cat >> filename

---------------------

--------------------

ctrl+d (save & quit)

33. To open multiple files:

# cat file1 file2 file3

Disadvantages:

Using this command we can't create multiple files and we can't edit the text at the file.

Touch:

This command is used to create multiple files, but are empty files and also it use to change date and time of an existing files and directories.

34. To create multiple files:

# touch f1 f2 f3

Disadvantages:

Using this command we can't modify the text of the database files.

35. change current Date and Time:

# touch f1

36. Change Time stamp of a file or directory

Syntax

# touch <option> <argument> <file/directory>

# touch –t YYYYMMDDHHMM <file/directory-name>

Deleting the files :

37. “rm” command is used for remove files

38. # rm <filename>

39. # rm -i <filename> --> asking confirmation

40. # rm -f <filename> --> delete file forcibility.

41. Remove multiple files at once

# rm <file 1> <file 2> <file 3>

Working with Directories:

“mkdir” (Make Directory) command is used for creating Directories.

Syntex: # mkdir <option> <Directory name>

42. To create a Directory

# mkdir <dir name>

43 Creating multiple directories

# mkdir dir1 dir2 dir3

44. Creating nested tree structure (sub directories inside directories)

# mkdir -p world/asia/india/ap/hyd/kphb

45. To check nested directories

# ls -R world

(or)

# tree world

Removing Directories:

46. “rmdir” (remove directory) command is used to delete an empty directory.

# rmdir <dirname>

47. “rm -r” command is used to delete recursively entire directory.

# rm -r <dirname>

48. # rm -ri <dirname> --> asking confirmation message

49. # rm -rf <dirname> --> remove forcefully.

Navigation Commands:

50. # cd --> To change a directory

51. # cd .. --> To move one level back

52. # cd ../.. --> To move two levels back

53. # cd - --> To go to the previous working directory

54. # cd <space-bar> --> To go to the users home directory

55. # cd <dir-name> --> To move to the particular directory.

Copying files and directories :

“cp” command is used to copy file or directory from one place to another.

56. To copy a file

# cp file1 file2

57. To copy a file into directory

# cp file1 dir1

58. To copy multiple files into a directory

# cp file1 file2 file3 dir1

59. To copy a directory

# cp -R <source directory> <destination dir>

# cp -R dir1 dir2

Move and Rename – Files and Directories :

“mv” (move) command is used to move files and directories from one place to another, and also this command is used to rename the file and directories.

Syntex: # mv <option> <source> <destination>

60. To move a file

# mv file1 dir1

61. To move a directory

# mv dir1 dir2

62. Renaming file and directory

# mv <old name> <new name>

Creating hidden files and directories :

To hide a file start file name with “.” character

63. # cat > .filename

64. # mv file1 .file1 (To hide existing file)

65. # mv .file1 file1 (To unhide a file)

66. # mkdir .dir1 (To create hidden directory)

67. # mv .dir1 dir1 (To unhide a directory)

68. # ls -l (or ll ) (Display longlist format, i.e, with 9 fields)

(i) File type, where '-' is a file and 'd' is a directory.

(ii) permissions of file or directory

(iii) Number of links (l) --> link file

(iv) owner of the file

(v) Group of file

(vi) File size in bytes

(vii) Creation data of file

(viii) Creation time of file

(ix) Name of file

Identify Files & Directories with colors:

# ls -l

Files - Black

Directories - Blue

Links - Skyblue

Zip - Red

Pages

Saturday, June 14

Unix Basic Commands with examples part 1

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