Smile is like a secret love note » Unix

Remove ^M from file in unix file

anilezfa — Sat, 10 May 2008 14:11:52 +0000

This note is dedicated to my chubby hubby that keep asking me how to remove ^M in a file.

UNIX treats the end of line differently than other operating systems. Normally CTRL-M character is visibly displayed at the end of each line as ^M if the file is not transfered in binary mode (this is why I always prefer SFTP instead of FTP).

In vi, to remove the ^M do as following :

:%s/^V^M//g

^V is a CONTROL-V character
^M is a CONTROL-M.

So it will look like this:

:%s/^M//g

%s is a basic search and replace command in vi.
The g is use for search and replace globally (all occurrences).

with Solaris you can just do (heard HPUX has the command “dos2ux” instead of dos2unix):

dos2unix

You can also use the octal representatiion of ^M:

tr -d ‘\015\032′ < file

semaphores and shared memory settings

anilezfa — Tue, 22 Apr 2008 02:08:58 +0000

shmsys:shminfo_shmmax
Maximum shared memory segment size

shmsys:shminfo_shmmin
Minimum shared memory segment size

shmsys:shminfo_shmmni
Number of shared memory identifiers

shmsys:shminfo_shmseg
Number of segments, per process

semsys:seminfo_semmap
Number of entries in the semaphore map

semsys:seminfo_semmni
Number of semaphore identifiers

semsys:seminfo_semmns
Number of semaphores in the system

semsys:seminfo_semmsl
Maximum number of semaphores, per ID

semsys:seminfo_semmnu
Number of processes using the undo facility

semsys:seminfo_semume
Maximum number of undo structures per process

Useful vi command – quick guide

anilezfa — Sun, 20 Apr 2008 17:12:54 +0000

Useful vi Commands

Cut/Paste Commands:

x	delete one character (destructive backspace)
dw	delete the current word (Note: ndw deletes n numbered words)
dd	delete the current line (Note: ndd deletes n numbered lines)
D	delete all content to the right of the cursor
d$	same as above
:u	undo last command
p,P	paste line starting one line below/above current cursor location
J	combine the contents of two lines
"[a-z]nyy	yank next n lines into named buffer [a-z]
"[a-z]p/P	place the contents of selected buffer below/above the current line

Extensions to the Above Commands:

:3,18d	delete lines 3 through 18
16,25m30	move lines 16 through 25 to after line 30
23,29co62	copy specified lines and place after line 62

Cursor Relocation commands:

:[n]	goto line [n]
shift g	place cursor on last line of text
h/l/j/k	move cursor left, right, down and up
^f/^b	move forward, backward in text, one page
^u/^d	move up, down one half page
$	move to end of line
0	move to beginning of line

Extensions to the Above:

b	move backwards one word (Note: nb moves back n number of words)
e	move to end of current word
(	move to beginning of curent block
)	move to the end of current block

Searching and Substitution commands:

/ [string]	search forward for string
? [string]	search backwards for string
n	repeat last search
N	repeat search in opposite direction
cw	change the contents of the current word, (use ESC to stop replacement mode)
c$	Replace all content to the right of cursor (exit replacement mode with ESC)
c0	Replace all content to the left of cursor (exit with ESC)
:1,$s/s1/s2/g	global replacement of string1 with string2
r	replace current character with next character typed

Entering the Insert Mode:

i	Begin inserting text at current cursor location
I	Begin inserting text at the beginning of the current line
a	Begin appending text, one character to the right of current cursor location
A	Begin appending text at the end of the current line
o/O	Begin entering text one line below\above current line
ESC	Exit insertion mode and return to command mode

Exiting and Entering VI

ZZ	save file and exit VI
:wq	same as above
:e!	return to last saved version of current file
:q	quit without save, (Note :q! is required if changes have been made)
:w	write without exit (:w! to force write)

Fancy Stuff:

:1,10w file	write lines 1 through 10 to file newfile
:340,$w >> file	write lines 340 through the end of the file and append to file newfile
:sh	escape temporarily to a shell
^d	return from shell to VI
:![command]	execute UNIX command without leaving VI
:r![command]	read output of command into VI
:r[filename]	read filename into VI
:$r newfile	read in newfile and attach at the end of current document
:r !sort file	read in contents of file after it has been passed through the UNIX sort
:n	open next file (works with wildcard filenames, ex: vi file*)
:^g	list current line number
:set	number show line numbers
:set showinsert	show flag ("I") at bottom of screen when in insert mode
:set all	display current values of VI variables
:set ai	set autoindent; after this enter the insert mode and tab, from this point on VI will indent each line to this location. Use ESC to stop the indentations
^T	set the autoindent tab one tab stop to the right
^D	set the autoindent tab one stop to the left
:set tabstop=n	sets default tab space to number n
>>	shift contents of line one tab stop to the right
<<	shift contents of line one tab stop to the left

Reset root password on linux red hat vmware

anilezfa — Fri, 18 Apr 2008 16:23:24 +0000

I forgot my root password on my linux vmware. Here are the steps that I do in order to reset it.

Press any key to go to the menu :
Press "e " when you see the following menu:
Select the image you want to load and press "e ":
Type " 1 " (fyi it space and number one) as in following screen and press enter :
Press "b " here to boot to single user:
You would get the following promt without being asked for password :
Type the change password command which is "passwd " and set your new password :
Reboot our system by typing "reboot " :
When prompt for password key in the new password just set up.
By now you should be able to login to the system :