Basic Commands -1.2

Creating files and adding data using cat command

Syntax :-

[root@localhost~]# cat <option> <arguments>

Example :- To create a file along with some data

[root@localhost~]# cat > salesreport

This file contains the sales report for the month Aug.

( Now press Ctrl+d to Save )

Example :- To create one more  file along with some data

[root@localhost~]# cat > mktgreport

This file contains the mktg report for the month of Aug.


( Now press Ctrl+d to Save )



Example :- To read the contents of a file

[root@localhost~]# cat salesreport

This file contains the sales report for the month of Aug.

Example : - To append (add) to a file

[root@localhost~]# cat >> mktgreport

This year the efforts in mktg have increased.

Ctrl+D

Check the contents of the file mktgreport

[root@localhost~]# cat mktgreport

This file contains the mktg report for the month of Aug
This year the efforts in mktg have increased.


Example :- To merge contents of two files into a third file

[root@localhost~]# cat salesreport mktgreport >> completereport

Check the contents of the file Completereport

[root@localhost~]# cat completereport

This file contains the sales report for the month of Aug.
This file contains the mktg report for the month of Aug.
This year the efforts in mktg have increased.

Creating 0 byte (empty) files using touch command

 Syntax :- Creating a single file with the touch command 

 [root@localhost~]# touch <filename>

Example :- Creating a single file with touch command

[root@localhost~]# touch file1

To check if the file has been created

 [root@localhost~]# ls -ld file1

-rw-r--r--. 1 root root 0 Aug 23 09:13 file1

Example :- Creating multiple file using the touch command

[root@localhost~]# touch file2 file3 file4

To check if the file has been created

 [root@localhost~]# ls -ld file*

-rw-r--r--. 1 root root 0 Aug 23 09:13 file1
-rw-r--r--. 1 root root 0 Aug 23 09:16 file2
-rw-r--r--. 1 root root 0 Aug 23 09:16 file3
-rw-r--r--. 1 root root 0 Aug 23 09:16 file4

To change the timestamp (date and time of modification) of a file or directory

Syntax :-

 [root@localhost~]# touch <option> <arguments> <file or directory name>

Example :- To change to the current date and time

[root@localhost~]# touch file1

To check if the timestamp has changed

[root@localhost~]# ls -ld file1

-rw-r--r--. 1 root root 0 Aug 23 09:20 file1

Syntax :-

[root@localhost~]#  touch -t YYYYMMDDHHMM <file or directory name>

Example :- To change to a different date and time

[root@localhost~]# touch -t 200905150842 file2

To check if the timestamp has changed

[root@localhost~]# ls -ld file2

-rw-r--r--. 1 root root 0 May 15  2009 file2