Tuesday, November 25, 2008

Command Hacks


man 4 console_codes


mount -t ntfs-3g /dev/sda6 /mnt/ -o force

Set the file system to particular partition
$mkfs.ext2 /dev/hda8
$mkfs.ext3 /dev/hda8
$tune2fs -j /dev/hda8 ---> ext2 to ext3
$blkid ----> you can use it to check the filetype of block device

How to create a partition from command line
$fdisk /dev/hda
>command(m for help): n
n for add new partition
>commandaction
>e extended
>p primary partition (1-4)
:p
>partition number(1-4):3
we are creating hda3
>First Cylender(1341-2438, default 1341):
to chose default just press Enter key
>Last cylinder or +size or +sizeM or +sizeK(1341-2438, default 2438): +56B
size is 56B
>p
> t
change a partition`s system id
>partition no(1-4):3
>Hexcode(type L to list codes): L
shows list
>hexcode(type L to list codes): 83



How to set IP address, Subnet mask , and gateway


The ip address can be assigned using ifconfig command
ifconfig "interface type" "ip address" "subnet mask" "broadcast address"
Ex:
ifconfig hme0 10.192.10.18 netmask 255.255.255.0 broadcast 10.192.10.255
ifconfig hme0 up

and the default gateway can be assigned in the /etc/defaultrouter file:

vi defaultrouter
10.192.10.1
:wq!

2) reset bootprom " " (just confirm using boot ? at OK prompt and to
come toOK prompt do init0)

Ref: http://unix.ittoolbox.com/groups/technical-functional/solaris-l/how-to-set-ip-address-subnet-mask-and-gateway-464377


Passwordless ssh login

1) Suppose you are login on 192.168.1.109
Type the following command to generate key
$ ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/root/.ssh/id_dsa): /root/.ssh/id_dsa
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_dsa.
Your public key has been saved in /root/.ssh/id_dsa.pub.
The key fingerprint is:
9f:7c:6c:a4:98:a7:25:03:cd:3c:4d:57:0e:c8:db:47 root@localhost.localdomain

2) Now copy this key to any computer.
$ssh-copy-id -i /root/.ssh/id_dsa root@192.168.1.31
root@192.168.1.31's password:
Now try logging into the machine, with "ssh 'root@192.168.1.31'", and check in:

.ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

Ref: http://www.linuxjournal.com/video/ssh-logins-without-passwords

Displays information about ELF files.

$readelf --segments /bin/ls
$readelf --segments /lib/libc.so.6
$readelf -a /bin/ls
 --------------------------------------------------------------------------------------------------
find command
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Sed -----------

Printing File Lines using Address and Patterns
Delete File Lines Using Address and PatternsLinkFind and Replace Text Inside a File Using RegEx
How To Write to a File Using Sed
Append, Insert, Replace, and Count File Lines
How To Execute Multiple Sed Commands
Multi-Line File Operation
Examples for Sed Hold and Pattern Buffer Operations


Ref: www.thegeekstuff.com
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Q. How to display a list of all manual pages containing the keyword "date", what command would you type?
Ans:  man -k date or apropos date

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