I'm trying to write a 100MB file for example all with 0xFF so in the hex editor it should look like "FF FF FF FF FF FF" etc. I know you can write a 0x00 with this line:
Code:
dd if=/dev/zero of=myfile bs=1M count=100
But how to do 0xFF or another character?
I want to use the 'dd' command because with the 'bs=1M' argument it is 100 times faster than any other shell command I've seen.
Code: cmd='date | wc'
$cmd If this script is executed, an error is generated. The reason written was that "The execution fails because the pipe is not expanded and is passed to date as an argument".What is meant by expansion of pipe. When we execute date | wc on the command line, it goes fine.then | is not treated as an argument. Why?
I was just wondering is 2.5mb a second normal to write to a usb2 pendrive with the 'dd' command?
I know dd maybe having an influence on writing time, but it still seems really low for usb2 transfer?
Is there a command to measure the time a file takes to transfer from HD to usb pen? (not using dd).
I am running a java application on centos. For now I have a gsm modem connected via the the usb cable. Below is the message I get when I type the command dmesg | grep tty
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
00:0c: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
usb 2-2: pl2303 converter now attached to ttyUSB0
[code]....
Currently we are using Unix machine & the activity are logged in the file using following code used in profile
.profile code
# /ln/aud_root/dds_ibm/.profile
trap 'print "not allowed"' INT
trap 'print "not allowed"' QUIT
trap 'print "not allowed"' TSTP
[Code].....
how to write a command (for loop) that would ping a Class C subnet to make it so that it only replies once and does not show the statistics?
View 2 Replies View RelatedWhen writing a script using command-line tools why is it more difficult using graphical tools?
View 3 Replies View RelatedI have the "top" command and I want to override its default behavior for every user, even for future users.
Writing with "W" in top is not an option as my top command somehow overrides the custom behavior per user and always turns to default behavior.
So, what I am asking for is, are there command line switches that override default behavior of top, for example:
Code:
top -<BLABLA>
to show me the load average per core which would be equivalent to starting top first and then pushing the key "1" on the keyboard.
Remember, writing to toprc is not an option for me as top for some reason ignores its config and just goes for default behavior.
Edit: it seems to me this is a bug in the procps package. That is why I updated it to the latest version for my distro CentOS 5.5 and procps to the following [URL] HOWEVER, it doesn't work even now.
I want to create a bootable iso on usb, however not an Ubuntu or any linux distro on my USB drive. How would I go about doing that on Ubuntu 10.10?
View 9 Replies View RelatedMy VPN is behaving funny sometimes, and I have to restart it often.I wanted to write a script which does that for me.It doesn't have to be anything fancy, just a shortcut for the commands I have to type into the terminal. More specifically: it will look at the running processes.If it finds a running vpnc process, it will kill it. Then it will start vpnc.I've written bash scripts of similar complexity,but now I don't have a bash,only an ash. Until now, the only difference I noticed is that there are much less commands available, but then, I don't use it very often.So I have some questions.
Is writing ash scripts different than writing bash scripts?
Is there something specific to consider when doing it?
When the script is ready, how can I deploy it? For bash, I just put the executable file under /usr/lib and run it by typing the file name into the command line, will this work with ash?
Are there any special pitfalls to watch out for in the script I want to write? I think that the killing process part may get hairy, if I write something that kills the wrong process, but even then running the script shouldn't break anything permanently, right?
I've just installed Ubuntu 10.10 amd64, and can't get DVD creator to work. I just slide in a blank DVD-R, and copy/paste the files onto it, and click "write on disc", the usual way... It does it, and then goes on with a checksum calculation which is almost longer than the copy itself. And then it says the copy failed, and sure enough, all files are corrupted.
PS: I don't know how it happens, but with every new relase of Ubuntu they break something with UDF DVDs.
10.04 couldn't read UDF DVDs until the RC stage, a few days before the actual release (they'd broken the /etc/fstab)10.10 couldn't read UDF in the early beta stages. And now even after release it still can't burn data DVDs.
I am trying to write into a single log file from 3 different applications in C. In one of the applications I am forking out 5 instances. I would like to know what is the best way to open and close the log file in which i want to write from these applications. Should I open and close it at the start and end of each application or is it ok performance wise if i open and close it inside the log function which will be called for every write.
View 6 Replies View Relatedi am having a the following line in a file
<property name="connection.password"></property>
i have to give password in this line, like this
<property name="connection.password">XXXXXX</property>
Is this possible to acheive this using sed command
Beause i have to do this for n number files. so if i have option in sed for this the i will be doing this using script.
I am going to write a TCP server program using c. Can anyone give me some advices on whats and what not to do specially when using select?
There would be a lot of data to be transferred both on the server and back to the client. I already have a simple server here but the server uses a lot of resources. Maybe 3 to 4 connections and the server's load would rise to unacceptable levels.
Which do you think is better to use fork or select?
I want to write some PHP for a website that'll have the data that the script will generate written inside a table with thin black line around it, much like LQ itself. My problem is: how do I draw the box that the text will be inside of, since the amount of text will vary - if I have a GIF with a picture of a box, that'll be of a fixed length, and my script can then only generate that much text, for it to look nice. Or do I need to fiddle with the GD library to get done what I want?
View 4 Replies View RelatedWhat does all the writing mean on this tee shirt?
View 14 Replies View RelatedIt frozen up occasionally, when that happens, usually the harddisk light lights up continuously. So I suspect some process is writing to the disk, which prevent other process to go on. how do I find out who's using a lot of IO?
View 3 Replies View Relateduser@user-laptop:~$ sudo dd if=sd_backup of=/dev/sdd bs=4M conv=noerror,sync
205520896 bytes (206 MB) copied, 28.564 s, 7.2 MB/s
247463936 bytes (247 MB) copied, 57.1285 s, 4.3 MB/s
260046848 bytes (260 MB) copied, 73.2388 s, 3.6 MB/s
289406976 bytes (289 MB) copied, 104.121 s, 2.8 MB/s
[Code]....
How come dd gets slower after copying this 8GB file? What can I do about it?
When you are performing time consuming operations in bash like installing new software, is it possible to write text that will appear at the prompt when the operation has finished.
E.g
Imagine running:
apt-get install eclipse-platform
Then it will use quite a while to finish while you see the installation log, meanwhile I want to create new folders (workspaces) which Eclipse later will use.
Is this possible without opening a new terminal (or tab)?
When I login I always do:
ssh myuser@111.111.111.111
Is it possible to do something like:
ssh myuser@server1
I would like to use a name, not an IP address, is it possible?
I had occasion to boot Ubuntu livecd yesterday on a Dell machine with XP installed. I pressed the Escape key during boot to see what might be happening behind the Graphic ...... and got a rather upsetting surprise ..... ... apparently Ubuntu was reading and writing to the XP partition ..... without any notification to me. I don't have the exact wording to hand, but what is said was that the XP install was 'dirty' and it was fixing it .... fixed! I used a 9.10 CD. Is there any information out there that addresses this behaviour? Is there a way to boot the CD and prevent this from happening? I do not expect or want ANY liveCD to write to ANY partition on ANY PC I might boot using that liveCD without my explicit permission/instruction. That this liveCD did write to a partition without asking or informing me is sufficient cause for me never to use such a liveCD again.
View 9 Replies View RelatedWhenever I plug-in my USB 8gb pendrive to copy a large file, it takes eons. Using Ubuntu 9.10 for AMD64. At first it copies a file at high speeds, because it's not actually writing to the USB but to the cache; at 500-700mb, the write cache is full and flushes, *while* still copying the rest of the file. Since the system is trying to access the USB in two different places at the same time, the transfer speed bunks down, often to 200-300kb/s. The final process, instead of taking 2 minutes, takes one hour.
This continues until 1.4gb, when the cache finishes the flush, the copy can continue streamlined and the last 200-300mb are copied again at quicker speeds. I've made a test, copying a 1.6gb file to the USB and waiting for the cache to get full. Once it happens, I copy another file of the same size to the USB at the same time, when it starts copying I cancel the previous copy - cancelling it could take 1-2 minutes, but once it's cancelled, the second copy goes amazingly quick since the pendrive doesn't have any access troubles anymore.
However, that means for the trick to work that I can't copy four 1.6 files to the 8gb pendrive, but only three. The fourth one would need an hour unless I start copying it just before the first three finish so the write cache is still not in use or something like that. So what I would want is that everytime I plug-in this specific USB drive (identified by its label or UUID), the automount parameters disable write caching for this drive. Is that feasible? Using fstab or how?
I've rolled a custom version of the live CD, and everything's going great on it.I was asked to make it a bootable USB stick as well.This was simple enough by installing UltraISO on my Windows box and writing the ISO to a USB stick through the 'Bootable' menu. But for some reason it boots up to a slightly less-pretty version of GRUB.That's all well and good, but now the language selection menu is gone. Is there any way to get that menu in the less-pretty GRUB? At the very least, is there a way to hard-code the language there so certain people have sticks with certain languages?
View 1 Replies View RelatedIve got a dedicated server setup to run the deluge daemon and access it through thee webui. i can add and even delete new torrents just fine but when i go into the options and try to change values like upload speed limits etc the changes dont take. im assuming this is a permissions issue but i don't know what files or directories to change.
View 1 Replies View RelatedI have a flash card that has been corrupted and have obtained a working .img file. I was told that I could not just drag and drop the .img to the card and that it needs to be written bit by bit to the new card. I am unfamiliar with the Linux terminal and would like to know what command or a how to get the .img file written to it. The .img file is now residing on the desktop.
View 3 Replies View RelatedI've just completed a fresh install on natty, and I'm seeing constant disk writes of around 1Mb every couple of seconds.
I looked at iotop to find the culprit, and it seems to be the journalling manager for the ext4 filesystems:
Code:
215 be/3 root 0.00 B/s 19.23 K/s 0.00 % 5.89 % [jbd2/sda1-8]
Is there something I can do to adjust this behaviour somehow? I'm a bit concerned about wearing the disk out before its time...
Basically I have a USB flash drive currently formatted under vfat. I can log in as root and the system automatically picks it up and automounts the drive successfully. What needs to happen is that a non-root user needs to be able write to this device while root has mounted this device. Due to other program constraints, I can not mount the device using another user so I have to do it with root.
View 9 Replies View RelatedI have a few Redhat 8 servers that I have shut the winbind service off, yet I see lots of message int he /var/log/messages log in regards to winbind. The message i am seeing are
pam_winbind[25640]: write to socket failed!
pam_winbind[25640]: internal module error (retval = 3, us
er = `root'
There is a lot of these messages in the log.
I need to write in Japanese, I know that I have to use iBus, but I don't know where to find it. I only know that it is installed, do you know where can I find it? I'm using Fedora 15
View 1 Replies View RelatedI'm trying to capture packets to a file with the -w option but the file is empty yet if I use the '-w -' option to put data on stdout I see plenty of captured packets.I'm using CentOS 5.5 x86
Code:
[root@server ~]# tcpdump -v -i eth0 -w dump -s0
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
[code]....