Note, when I specify something in brackets like so: [filename] that is to indicate that you type in a filename or whatever. Do not include the brackets in your command.

Navigating UNIX:

/ (refers to the root directory on the server)
./ (the current directory that you are in)
../ (parent directory of your current directory)

pwd (shows what you current directory is - giving the full path)

ls (lists all the files in your current directory)
ls -al (lists filenames + information)
ls -alR (lists filenames + information in all subdirectories)
ls -alR | more (lists filenames + information in all subdirectories,
pausing when the screen become full)
ls -alR > result.txt (lists filenames + information in all subdirectories,
and ouputs the results to a file instead of the screen)
ls *.html (lists all files ending with .html)
ls -al /home/usr/bob/ (lists files + info for /home/usr/bob)

cd (changes you to a new directory)
cd images
cd / (changes you to the root directory)
cd /home/usr/images
cd .. (this goes back one directory)

Moving, Copying and Deleting Files:

mv [old name] [new name] (move/rename a file)

cp [filename] [new filename] (copy a file)

rm [filename] (delete a file)
rm * (delete all files in your current directory)
rm *.html (delete all files ending in .html
in your current directory)

Creating, Moving, Copying and Deleting Directories:

mkdir [directoryname] (creates a new directory)

ls -d */ (lists all directories within current directory)

cp -r [directoryname] [new directoryname] (copy a directory and all
files/directories in it)

rmdir [directoryname] (remove a directory if it is empty)
rm -r [directoryname] (remove a directory and all files in it)

Searching Files and Directories

find / -name [filename] -print (search the whole server for a file)
find . -name [filename] -print (search for a file starting with
the current directory)
find / -name [directoryname] - type d -print
(search the whole server for a direcory)

grep [text] [filename] (search for text within a file)

sed s/[oldtext]/[newtext]/g [filename] (searches file and replaces all occurances of [oldtext] with [newtext]

Viewing and Editing Files:

tail [filename] - view the tail end of a file, useful for checking the error log
when debugging a script

vi [filename] - opens a file using the vi text editor. you are a true geek if you use vi, however it’s fairly easy to use. (refer to the vi primer in this support forum)

Installing Software & Scripts

For downloaded ‘tar’ scripts, to un-tar and un-gz
tar -xvf [archive.tar] - extracts files from the tar archive ‘archive.tar’
tar -zxvf [archive.tar.gz] extracts files from the tar archive ‘archive.tar.gz’

Getting Server Information

which perl displays the path to perl

For viewing disk space.
du to view disk usage on server
quota to view your disk usage on server

whoami - displays your current username

uptime - displays how long the server has been up and some performance statistics

ps - displays running processes

top - (may be only available to admins) similar to windows task manager

kill -9 [process Id] - terminiates a running process (out of control CGI, etc). The process Id can be obtained using “ps”

File and Directory Permissions

There are three levels of file permission: read, write and execute. In
addition, there are three groups to which you can assign permission,
The file owner, the user group, and everyone. The command chmod followed
by three numbers is used to change permissons. The first number is
the permission for the owner, the second for the group and the third
for everyone. Here are how the levels of permission translate:

0 = — (no permission)
1 = –x (execute only)
2 = -w- (write only)
3 = -wx (write and execute)
4 = r– (read only)
5 = r-x (read and execute)
6 = rw- (read and write)
7 = rwx (read, write and execute)

I prefer that the group always have permission of 0. This prevents other
users on the server from browsing files via Telnet and FTP. Here are the
most common file permissions used:

chmod 604 [filename] (minimum permission for www HTML file)
chmod 705 [directoryname] (minimum permission for www directories)
chmod 705 [filename] (minimum permission for www scripts & programs)
chmod 606 [filename] (permission for datafiles used by www scripts)
chmod 703 [directoryname] (write-only permission for public FTP uploading)

Note that some systems use AFS filesystem and chmod does not behave as expected.You can sometimes identify AFS if the path that you are using begins like so /afs/path/to/files/ If your system uses AFS, then the following commands are used instead of chmod.

fs setacl [directory] [group] [access] (set file permissions)
fs listacl [directory] (list file permissions)

example:

fs setacl . httpd rliw (set read, lookup, insert, write to http for current dir)

Scheduling Tasks

You can schedule tasks to run automatically by using the UNIX cron command.
To use this, you create a text file with cron instructions, then process
this file. cron instructions are basically UNIX commands with extra info
about the time that they will run.

One important thing to note is that it is best to use full paths when
creating your cron file. As an example, create a file called mycronfile
and in it place one line:

0 1 * * * cp /usr/www/file.txt /usr/www/backup.txt

now at the command line, type the following:

crontab mycronfile

You have just scheduled an automated task! This task will run at the time
specified until you decide you want to cancel it.
There are six fields in this file. The first five represent the time that
the job will run. The sixth field is a UNIX command that will run at the
specified time. The above example will run every night at 1AM, at which
time it will copy a file.

Here is how the fields break down:

Field 1 | Field 2 | Field 3 | Field 4 | Field 5
Minutes | Hours | Day of Month | Month | Day of Week
(0-59) | (0-23) | (1-31) | (1-12) | (0-6)

You can enter a number in the field, a range of numbers, or an * to indicate all.
Here are a few more examples. These examples use the ls command, which would be
pretty useless. Note the time that it runs, though.

0 1 * * 1-5 ls (this would run every Monday-Friday at 1am)
0 1 * * 1,3,5 ls (this would run every Monday, Wednesday and Friday at 1am)
10 2 1 * * ls (this would run at 2:10am on the first of every month)
0 1 1 1 * ls (this would run at 1am on January 1 every year)

If you have a more complicated command that you want to run, it is sometimes
helpful to create a shell script and have that script run. You specify the
shell script as you would any UNIX command. For example:

0 1 * * * /usr/www/myscript

There are some other crontab switches that are useful:

crontab -l (lists your currently scheduled tasks)
crontab -r (delete all currently scheduled tasks)
crontab -e (directly edit your scheduled tasks)

Credits
——–

Originally created by J. Hinkle
Additional content provided by Dave Wojo
Copy & Paste by Iter.blogsome

here is the tutorial Ubuntu USB-Serial port install procedure.

If you are using the usb -> RS232 adapter, the serial drivers may need to be installed for the device to work properly. After plugging in the device, first check the hardware messages to see the device was detected:

dmesg

Torward the end of the messages, you should see this:

usb 1-1: new full speed USB device using uhci_and address 2
usb 1-1: configuration #1 chosen from 1 choice

Now, we need to figure out the device vendor number and product number to tell the usbserial driver. For this we can use lsusb. The easiest way to find the information is to first unplug the device, then run lsusb:

lsusb

You will see a summary list of your USB devices on the system, I only have one:

Bus 001 Device 001: ID 0000:0000

Now, plug the device back in, and run lsusb again:

lsusb

Which returns the summary list again, but now showing the new USB device:

Bus 001 Device 002: ID 4348:5523
Bus 001 Device 001: ID 0000:0000

Now, we can load up the driver for this device:

sudo modprobe usbserial vendor=0x4348 product=0x5523

Finally, check dmesg again to ensure it loaded properly.

dmesg

Near the end, you should see something like:

usbserial_generic 1-1:1.0: generic converter detected
usb 1-1: generic converter now attached to ttyUSB0
usbcore: registered new interface driver usbserial_generic

Congratulations, your link is up - in this example, the device can be used on /dev/ttyUSB0. As much fun as you had doing this, there is some chance you want to do this automatically in the future. Just add this line:

usbserial vendor=0x4348 product=0x5523

to /etc/modules with the vendor and product numbers you found. Now, you should have no problem using this device like a normal serial port.

My new laptop doesn’t have a serial port. This is one of the great tragedies of modern laptops in my opinion. At least for situations where I want to connect to the serial port on a server or system with a serial port, I can use a USB to serial adapter like this adapter I bought at NewEgg. I tested it just now by connecting to the serial port on my old FreeBSD laptop.

First I enabled the serial port in /etc/ttys

#ttyd0 “/usr/libexec/getty std.9600″ dialup off secure
ttyd0 “/usr/libexec/getty std.9600″ dialup on secure

Then I restarted init to activate it.

# kill -HUP 1

On my Ubuntu laptop I attached the USB to serial adapter to a null modem and a gender changer, then connected it to the FreeBSD laptop serial port.

I installed cu(1) on Ubuntu

# apt-get install cu

then checked dmesg output to ensure I had a device to which I could connect.

[17213831.716000] usb 1-1: new full speed USB device using uhci_hcd and address 2
[17213831.876000] usb 1-1: configuration #1 chosen from 1 choice
[17213831.984000] usbcore: registered new driver usbserial
[17213831.984000] drivers/usb/serial/usb-serial.c: USB Serial support registered for generic
[17213831.984000] usbcore: registered new driver usbserial_generic
[17213831.984000] drivers/usb/serial/usb-serial.c: USB Serial Driver core
[17213831.988000] drivers/usb/serial/usb-serial.c: USB Serial support registered for pl2303
[17213831.992000] pl2303 1-1:1.0: pl2303 converter detected
[17213831.992000] usb 1-1: pl2303 converter now attached to ttyUSB0
[17213831.992000] usbcore: registered new driver pl2303
[17213831.992000] drivers/usb/serial/pl2303.c: Prolific PL2303 USB to serial adaptor driver

Now that I saw /dev/ttyUSB0 was enabled, I connected to it.

richard@neely:~$ cu -l /dev/ttyUSB0
Connected.

FreeBSD/i386 (orr.taosecurity.com) (ttyd0)

login: richard
Password:
Last login: Fri Mar 16 11:57:49 on ttyv1
Copyright (c) 1992-2006 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
The Regents of the University of California. All rights reserved.

FreeBSD 6.1-SECURITY (GENERIC) #0: Wed Feb 14 15:33:28 UTC 2007

Welcome to FreeBSD!

That’s it. If I needed to set a different speed I’d use the -s switch. For example, if 9600 above was 19200 in /etc/ttys, I’d use syntax like

richard@neely:~$ cu -l /dev/ttyUSB0 -s 19200

Now I know I can rely on this USB to serial adapter when I visit servers in the data center.

#adduser username
Enter new password: (type your user password)
Re-enter new password: (type your user password)

2. Backup of a compact flash card is done by imaging it, often referred to as ‘ghosting’. To restore ghosted images of the compact flash card to a saved stated is done with the dd command. ‘dd’ is a standard Linux tool installed on most desktop distributions.

To backup the CF card, followed command is used:
dd if=/dev/sda of=my_backup_file
‘if’ is the input file, and ‘of’ is the output file.

To restore the CF card, the compact flash disk is specified as the output:
dd if=my_backup_file of=/dev/sda

*Purpose of doing this is to make a backup for the karnel. If something happened and the board OS corrupted, then user can use this image to restore the ts7200 OS.

it is a great for mac and linux user.. there is an application such as matlab.. it free … it give me a big smile..

GNU Octave is a high-level language, primarily intended for numerical computations. It is similar to the commerial product MATLAB. It gives you an command line environment where you can do calculation, solve equations, manipulate matrices and plot graphs. A list of commands can be put into a file and executed as an interpreted scripting language.

A simple example of a Octave session
octave:1> a = 2 * 3
a = 6
octave:2> b = [ 1 2 3 4]
b =

1 2 3 4

octave:3> c = a * b
c =

6 12 18 24

octave:4> exit

source:ubuntu

$ su root

$ sudo su (for ubuntu user)

Minicom is a text-based, serial communications program designed for Linux and distributed under the Free Software Foundation GNU Public License.

1. By default, minicom is not installed in Ubuntu, so user need to install it first.
sudo apt-get install minicom
2. Find the name of your Serial Port
dmesg | grep tty
In the output look for something like “tty”. The output in my case is like this:
$ dmesg | grep tty
[ 17.341823] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 17.342454] 00:0b: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
This means the device correspond to serial port is ttyS0.
3. Configure minicom
sudo minicom -s
o Use the keyboard keys to select the menu item Serial port setup.
o Enter A to change the Serial Device to /dev/ttyS0, and then enter E to change the line speed to 115200 8N1
o Using arrow keys, select Save setup as dfl
4. Select Exit from Minicom.
5. Next time, from the terminal user only need to run sudo minicom in order to access the TS7200 SBC.

I was using Ubuntu 7.04

For windows we can use Telix and in Linus as usually use minicom. Actually this two is same things because it communicate using serial communication. Minicom is a clone of the MS-DOS Telix communication program. It emulates ANSI and VT102 terminals, has a dialing directory and auto zmodem download. You can go here for more information.

My problem now is i cannot use the USB to Serial Port Converter. I already install the application from the CD given but still cannot use it. When i open up my HyperTerminal ( Start > All Programs >Accessories>Communication>HyperTerminal) it show the connection using COM3 but I need COM1 to connect the ARM TS7200 SBC. I also had read some great tutorial on how we can use this USB to Serial Port Converter here. Honestly I did not success install the USB and hopefully I can find another great tips to overcome my problem. Your suggestion and idea are most welcome.

I have a project to done using this ARM SBC ts7200. The title of this project is EMBEDDED LINUX INSECT DATA COLLECTOR. Actually i didn’t like the title a bit and it suppose to be INSECT RECOGNITION USING TS7200 because my task is to build up a tools to recognize the insect. It a bit difficult for me to start doing this project because i am very new in Linux so i really welcome any idea from the readers what should i do. My achievement for now is i can communicate with the ts7200 board using minicom. In future i would like to interface the board with LCD and Keypad. As i said before i am new in Linux, so i need your suggestion where can i fine a tutorial to work on LCD and Kedpad. I do have a little bit on C programming . After finish this stage, i want to interface the board with webcam. Huh… it kinda difficult for me… so I am looking some great guidance and tutorial from you all. TQ