Unix is operating system is come in 1969 at AT&T bell labs by Ken Thompson and Dennis Ritchie.
KERNAL- It is heart of OS. is intract with H/W. also most of work like task management ,memory management etc.
SHELL- It is utility to process request .is tell the what to do to OS.C shell, Bourne Shell,Krone Shell.
$ls -l
total 1962188
drwxrwxr-x 2 amrood amrood 4096 Dec 25 09:59 uml
-rw-rw-r-- 1 amrood amrood 5341 Dec 25 08:38 uml.jpg
drwxr-xr-x 2 amrood amrood 4096 Feb 15 2006 univ
drwxr-xr-x 2 root root 4096 Dec 9 2007 urlspedia
-rw-r--r-- 1 root root 276480 Dec 9 2007 urlspedia.tar
drwxr-xr-x 8 root root 4096 Nov 25 2007 usr
drwxr-xr-x 2 200 300 4096 Nov 25 2007 webthumb-1.01
-rwxr-xr-x 1 root root 3192 Nov 25 2007 webthumb.php
-rw-rw-r-- 1 amrood amrood 20480 Nov 25 2007 webthumb.tar
-rw-rw-r-- 1 amrood amrood 5654 Aug 9 2007 yourfile.mid
-rw-rw-r-- 1 amrood amrood 166255 Aug 9 2007 yourfile.swf
drwxr-xr-x 11 amrood amrood 4096 May 29 2007 zlib-1.2.3
$
Here is the information about all the listed columns:
First Column: represents file type and permission given on the file. Below is the description of all type of files.
Second Column: represents the number of memory blocks taken by the file or directory.
Third Column: represents owner of the file. This is the Unix user who created this file.
Fourth Column: represents group of the owner. Every Unix user would have an associated group.
Fifth Column: represents file size in bytes.
Sixth Column: represents date and time when this file was created or modified last time.
Seventh Column: represents file or directory name.
In the ls -l listing example, every file line began with a d, -, or l. These characters indicate the type of file that's listed.
| Prefix | Description |
|---|
| - | Regular file, such as an ASCII text file, binary executable, or hard link. |
| b | Block special file. Block input/output device file such as a physical hard drive. |
| c | Character special file. Raw input/output device file such as a physical hard drive |
| d | Directory file that contains a listing of other files and directories. |
| l | Symbolic link file. Links on any regular file. |
| p | Named pipe. A mechanism for interprocess communications |
| s | Socket used for interprocess communication. |
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cp source destination
exp: cp /oracle/anurag/test.txt /oracle/
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Move file to one location to another location
(cut & paste)
mv /oracle/test.txt /iptv/rest/
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Delete
rm test.txt
rm test1.txt test2.txt test3.txt
rm -rf anurag.txt (its remove the file without asking )
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mkdir /test
mkdir -p /test/test1/test2/test3/
(is create parent and sub folder)
rmdir /anurag
(but directory should be empty)
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File Permission
-rwxr-xr--
r : read-4
w : write (modify)-2
e : execute-1
- : no permission-0
rwx wrx xw-
first 3 -owner
second 3 - group
third 3 - others
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Directory permission
chmod
To set/modify a file's permissions you need to use the chmod program. Of course, only the owner of a file may use chmod to alter a file's permissions. chmod has the following syntax:chmod [options] mode file(s)
The 'mode' part specifies the new permissions for the file(s) that follow as arguments. A mode specifies which user's permissions should be changed, and afterwards which access types should be changed. Let's say for example:chmod a-x socktest.plThis means that the execute bit should be cleared (-) for all users. (owner, group and the rest of the world) The permissions start with a letter specifying what users should be affected by the change, this might be any of the following:
- u the owner user
- g the owner group
- o others (neither u, nor g)
- a all users
This is followed by a change instruction which consists of a +(set bit) or -(clear bit) and the letter corresponding to the bit that should be changed.
chmod 777 /oracle/test.txt
-rwxwrxxwr
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Compress folder using tar command
tar -cvf /db/test.tar /test
if folder size greater then 8GB the use
tar -cvEf /db/test.tar /test
