Monday, August 8, 2011

[Alpha version] Now it is simple to install rpm packages on other pc which don't have internet connection.

Run this script package-script.sh from the system which has internet connection then copy the package.tar.gz file.

Now,
How to install packages on other pc which don't have internet connection.
1. paste package.tar.gz into non-internet pc.
2. Switch to root user using
$ su -
3. Extract tarball
# tar -C packagepkd -xvf package.tar.gz
4.
# cd packagepkd/.package/
5. rpm -ivh ....
check "man rpm" for more details.

Note:

Kindly, report here if you find any bug.

How to remove all *.lnk files from pen drive

Yesterday, I have connected my pen drive on someone else's system. Now, when I return home and connected my pen drive on my system, I have found lnk files for each file and directory in my pendrive. It is a waste of time deleting those files one by one. So, here is a simple command to remove all lnk files.

# find /path/to/pendrive -name '*.lnk' -exec rm -v '{}' ';'

Friday, July 8, 2011

How to change MAC address in fedora

1. First step is to find the current MAC address and take a backup copy in a safe place.

To know your current MAC type:
$ ifconfig | grep HWaddr
eth0 Link encap:Ethernet HWaddr 00:19:48:2E:D1:27

The above hexadecimal numbers 00:19:48:2E:D1:27 is your MAC address for device eth0.
Simply copy and paste it in a file.

2. Now, time to change the MAC address this requires you to work as root user.
Take the network interface down
# ifdown eth0

Now, lets change the current MAC address to 00:E0:81:5C:B4:0F
# ifconfig eth0 hw ether 00:E0:81:5C:B4:0F

Take the network interface up again
# ifconfig eth0 up

Check if your MAC address is changed:
# ifconfig eth0 | grep HWaddr

Note:
Changing MAC address is only temporary. Once you reboot your machine, the operating system will reflect the physical MAC address burnt in your network card and not the MAC address you set.

Thursday, July 7, 2011

Default Permission

Default Permission:
For Normal Users:-
1. On File:
-rw-rw-r-- or 664
2. On Directory:
drwxrwxr-x or 775

For users with root permissions:-
1. On File:
-rw-r--r-- or 644
2. On Directory:
drwxr-xr-x or 655

File and Directory Permissions

File Permissions:
1. -r--
content of the file can be read using command such as cat, less or more.
2. -rw-
Note: read permission is required to write into any file.
file can be edited and saved
3. -r-x
Note: read permission is required to execute any file.
shell (bash or sh, etc) will attempt to execute the file when file's name is entered as a command.

Directory Permissions:
1. dr--
content of directory can be read as ls.
Few examples:
$ ls testing/
ls: cannot access testing/file2: Permission denied
ls: cannot access testing/file1: Permission denied
file1 file2

Note: long listing requires execute permission.
Few examples:
$ ll testing/
ls: cannot access testing/file2: Permission denied
ls: cannot access testing/file1: Permission denied
total 0
-????????? ? ? ? ? ? file1
-????????? ? ? ? ? ? file2

2. d-wx
files may be created or delected in the directory.
Note:
a). execute permission required.
b). A file can be deleted by anyone who has write permission to directory in which the file resides regardless of the ownership or permission for that file.
Few examples:
a). $ ls testing/ [Failed]
ls: cannot open directory .: Permission denied

3. d--x
enter into directory using command cd
Few examples:
a). $ ls testing/
ls: cannot open directory testing/: Permission denied
b). $ cd testing/ [Okay]

Tuesday, June 14, 2011

[Solved] Starting LSB: start and stop the WLM configuration [1;31mfailed [0m, see 'systemctl status cgconfig.service' for details.

Most simple solution:
# yum update libcgroup-0.37.1-3.fc15

My problem is solved after this update.

[Solved]- Starting /dev/disk/by-uuid/ad5290fc-d073-45db-bfaf-86f25f401a07 [1;31maborted [0m because a dependency failed.

If you got any error like this at f15 booting time:
Starting /dev/disk/by-uuid/ad5290fc-d073-45db-bfaf-86f25f401a07 [1;31maborted [0m because a dependency failed.
Case I:
First check your /etc/fstab,
if you got any line starting with
UUID=ad5290fc-d073-45db-bfaf-86f25f401a07
Note: In my case UUID=ad5290fc-d073-45db-bfaf-86f25f401a07. But in case UUID will be something else.

Reason:
Reason for this failed message can be due to change in the partition like partition recreated after delete or filesystem type change (say ext3 to ext4).

Solution:
If it is due to change in partition you can use any one of the two methods:
1. Use blkid to find the UUID of /dev/sda5 (say the partition which has been changed is /dev/sda5)
# blkid
copy the UUID value from the output of the above command for /dev/sda5 only and paste it in place of previous UUID in /etc/fstab

Note: If the changed partition is your root partition you must have to edit /etc/grub.conf file
root=UUID=^new UUID^

2. open /etc/fstab file as root.
Now, edit only first field.
for example:
if it is like:
UUID=ad5290fc-d073-45db-bfaf-86f25f401a07 swap swap defaults 0 0
Replace the first field with partition name /dev/sda5 (say the partition which has been changed is /dev/sda5)
/dev/sda5 swap swap defaults 0 0
Note: If the changed partition is your root partition you must have to edit /etc/grub.conf file
root=/dev/sda5 (say the partition which has been changed is /dev/sda5)