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Posts from the ‘Linux’ Category

oops i cann’t boot my windows because of before linux was installed on my machine

Steps below

  1. Before removing a partition, boot rescue mode
  2. Start parted ,where /dev/hda is the device on which to remove the partition
  3. In command mode
  4. >list hard-drives
  5. >parted /dev/hda or /dev/sda
  6. >print
  7. >rm 2
  8. exit and then you can install another OS on your system like windows xp or any.
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step by step redhat installation on vmware

This document show you step by step redhat installation on vmware workstation

 

Step by step redhat installation on VMware workstation

insufficent disk space you need more space on the following file systems: 167m on /mnt/sysimage/usr

While you’re trying to install Linux, you may face this issue

”  there was an error running your transaction for the following reasons insufficent disk space

you need more space on the following file systems: 167m on /mnt/sysimage/usr “

redhat_40

Solution : Increase the /usr partition size, you might be given a very less size while you’re done partition. Increase the size at least 5GB for /usr

How do i set linux file permissions using symbolic mode

If you want to set the file permissions in Linux, you can get a two options to set the appropriate permissions of files. One is Symbolic method and Numeric method. Here you can read about symbolic method examples.

The chmod (change mode) command will useful to change your file permissions. First of all I want to explain about how do i set appropriate file permissions for user, groups and others. Here others means Everybody (users) can able to view the files or ability to change the file contents if you give permissions.

The basically Linux file is 9 rightmost bits in 10bits permissions block.

Example :

rw-rw-rw- 1 root   root       889 Nov 10 10:59 1millions.txt

Which user :

u  --> user

g  --> groups

o  --> others

a   --> all

What to do ?

+   --> add this permission

-  --> remove this permission

= --> set exactly this permission

Which permissions :

r  --> read

w   --> write

x  ---> execute

Let’s see some examples :
Example 1: Set read write permission of this files for all

[root@siebelts u01]# chmod a=rw 1millions.txt

[root@siebelts u01]# ls -l 1millions.txt
-rw-rw-rw- 1 root root 889 Nov 10 10:59 1millions.txt

Example 2: Want to remove write permission for all users

[root@siebelts u01]# chmod a-w 1millions.txt
[root@siebelts u01]# ls -l 1millions.txt
-r--r--r-- 1 root root 889 Nov 10 10:59 1millions.txt
[root@siebelts u01]#

Example 3: Set the write permission for owner of this file

[root@siebelts u01]# chmod u+w 1millions.txt
[root@siebelts u01]# ls -l 1millions.txt
-rw-r--r-- 1 root root 889 Nov 10 10:59 1millions.txt

Example 4: set write and execute permission for groups

[root@siebelts u01]# chmod g+wx 1millions.txt
[root@siebelts u01]# ls -l 1millions.txt
-rw-rwxr-- 1 root root 889 Nov 10 10:59 1millions.txt
[root@siebelts u01]#

Example 5: set read and write  permission for other user also

[root@siebelts u01]# chmod o+rw 1millions.txt
[root@siebelts u01]# ls -l 1millions.txt
-rw-rwxrw- 1 root root 889 Nov 10 10:59 1millions.txt
[root@siebelts u01]#

Example 6 : remove the write, execute permission of  groups and others

[root@siebelts u01]# chmod g-rw 1millions.txt && chmod o-rw 1millions.txt
[root@siebelts u01]# ls -l 1millions.txt
-rw---x--- 1 root root 889 Nov 10 10:59 1millions.txt

Example 7: Let’s see i change the groups of this file and try to write on this file.

[root@siebelts u01]# chown :oinstall 1millions.txt
[root@siebelts u01]# ls -l 1millions.txt
-rw---x--- 1 root oinstall 889 Nov 10 10:59 1millions.txt
[root@siebelts u01]# su - oracle
[oracle@siebelts ~]$ vi /u01/1millions.txt

"/u01/1millions.txt" [Permission Denied]
[oracle@siebelts ~]$

Example 8: set write permission of this file and try to write using member of the oinstall group

[root@siebelts u01]# chmod g+rw 1millions.txt
[root@siebelts u01]# ls -l 1millions.txt
-rw-rw---- 1 root oinstall 32 Nov 11 04:25 1millions.txt

[root@siebelts u01]# cat 1millions.txt
File permission symbolic test
[root@siebelts u01]# su - oracle

[oracle@siebelts ~]$ cd /u01
[oracle@siebelts u01]$ vi 1millions.txt
[oracle@siebelts u01]$ cat 1millions.txt
File permission symbolic test
File can be write and read by member of oinstall
[oracle@siebelts u01]$

Reference : Tuxfiles Linux File permissions

Linux How do i view top two lines of files


[oracle@siebelts ~]$ head -n 2 /u01/app/oracle/diag/rdbms/crmtest/crmtest/trace/alert_crmtest.log
Wed Dec 07 04:46:19 2011
Starting ORACLE instance (normal)