General :: "how To" Way In Understanding The Commands Used In The CLI
Apr 9, 2010I am having a hard time understanding how to order the commands in the CLI. Its like I don't have a clue as to what do next.
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Ubuntu :: Understanding Roles Of Commands: At - Batch And Anacron
Nov 19, 2010I'm trying to understand the role of the at command. Does cron use at to run its jobs? Or is at, and batch for that matter, a separate cue that is only stored while the computer is on. As for anacron, anacron on runs once a day and is geared for a computer that is turned of frequently, as opposed to a server when it is on all the time. I've already man'ed these commands, and googled. I'm just trying to understand more how they work.
View 2 Replies View RelatedGeneral :: DD Imaging Of Builds Better Understanding
Nov 12, 2010I am learning how to use DD for creating images across networks and locally but needed some clarification.
1 - When creating an image, I noticed that there is no verbose to show you the progress, How can I accomplish this?
2 - When I run this on a 8G usbstick it takes a long time to image. How can I speed up this process?
PHP Code:
dd if=/dev/sdb of=/home/test/images/image.dd
3 - When an image is restored like
PHP Code:
dd if=/home/test/images/image.dd of=/dev/sdb
will that give me a working bootable usbstick? For example if I imaged a working usbstick with Ubuntu on it using DD and restored it like the example above on a different usbstick, will this give me a booting new usbstick? I hope that came across ok?
General :: Understanding How Pipe Works In Bash
Aug 21, 2010I don't quite understand how pipes work in bash. I know that it takes an output from one command as the input in another command. What an output is I can get because it's what the command prints out to the screen. But how do I know what input a command will take? Here is an example I thought would work:
Which gem | rm
Unfortunately it didn't.
Which gem prints out "/usr/bin/gem" so that must be the output right? I thought that was given to rm so it would be "rm /usr/bin/gem" but I was wrong. How do I know what input a command takes?
General :: Finding An Appropriate Distro And Understanding Setup?
Aug 11, 2010I'm trying to set up a machine to "drive" a piece of equipment (a metal plate embosser [kind of like a daisywheel printer for credit card sized pieces of metal], FWIW). What I ideally want is a linux distro that I can boot from CD (I think the term is Live CD?), log itself in as a user and display only a console. It needs to be able to support windows fileshares and python.
Essentially it needs to boot, connect to a single fileshare on a Win2k8 machine, and be able to execute a couple of scripts that will output to a serial port. One of them will be more or less the following:
wget http://WEBSITE/?<parameter passed to script> --quiet --output-document=<name of serial port>
The other is a somewhat more complicated Python script that processes a CSV spreadsheet and produces data for the machine.
General :: Understanding Md5 Password Placement In Grub?
Jul 13, 2011My grub file looks like this:-
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
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General :: Understanding Ubuntu User / Group Permissions
May 20, 2010I'm beginning to deal with more than one user on my system (it's a VPS serving some sites) and I need to make sure I understand how group permissions work. I have an account named "admin" .. it's basically the primary account that is used for serving most of the sites that I control myself. Now, I added a second account named "Ville" as one of my users wants to be able to administer that site. So, I can do this the easy way and just chown their domains folder under the ville user, they have permission to do whatever they need be and so forth. However, let's say I want to also give the admin user access to the files (modifying and all) .. how can I put both users into the same group and give them both permission?
I've tried doing:
sudo usermod -a -G admin ville
To add the ville into the admin group, but ville still cannot edit files by admin. Permissions for the primary directory for the ville user are read/write for both owner and group, and the current group for the files is admin:admin ..
But ville still can't write into the directory. So, what should I be doing here to get this right and secure at the same time?
General :: Compiling Programs - Understanding Concept Of Makefile2
Jan 13, 2011# Filename: makefile2
# Usage: make-f makefile2
# Description: Maintains all the dependencies between modules using the
# Agenda1.
CC=g++
CFLAGS=-c -Wall
LDFLAGS=
SOURCE_MODULES=main.cpp factorial.cpp hello.cpp
OBJECT_MODULES=$(SOURCE_MODULES:.cpp=.o)
EXECUTABLE=programa1
all: $(OBJECT_MODULES) $(EXECUTABLE)
$(EXECUTABLE): $(OBJECT_MODULES)
$(CC) $(LDFLAGS) $^ -o $@
.o: .cpp
$(CC) $(CFLAGS) $< -o $@
I am suppose to explain the dependencies that exist and each of the following lines of makefile. Lists orders to be executed as a result of running the make utility on it.
General :: Lack Basic Understanding Of Permissions (Apache)
Apr 8, 2010I am very new to linux. The first time i ran a linux machine was one Saturday. Anyway I am trying to set up an apache web server, all I want to do is play around with html and post it on my unbuntu server so it is available to the internet. I am also trying to install samba but I am having trouble with that so for now I am using winscp. Ok, so I made a folder in my home directory for webstuff, and set up apache to look in that folder.
mkdir /home/username/webstuff
I put my index.html file into the /webstuff folder.
But when I go to my website, it says 403 error unable to access "/"
Did I make the folder in the right place? I do not want people being able to access my / folder so maby I made the web stuff folder in the wrong place? Also I thought I would just put my inded.html file inside of the default one apache gives you, but when I tried to transfer index.html it said permission denied. How to set up permissions so I can use apache and transfer my html files from my remote desktop to my server would be great!
General :: Understanding Idle/Inactive Sessions And Whether Or Not Someone Is Logged In?
Jan 5, 2011I'm trying to understand if anyone is left on a server. Basically I manage a simple linux server remotely used by 3-4 individuals. I can never tell if someone is actually on or not using w/who.What I'm seeing is some people having what appears to be inactive/lost VNC sessions. I don't understand idle fully, but I do believe a program (without user interaction) can clear idle back to 0, correct?Anyway, I'm asking because every now and then I need to reboot the server, and I do not want to interrupt any program working on calculations or waiting on having the data saved.
Code:
me@matrix:~> w
06:59:54 up 170 days, 9:13, 16 users, load average: 0.52, 0.16, 0.06
[code]....
General :: Get A General Understanding Put Simply?
Apr 3, 2010Im trying to get a general understanding put simply.
View 6 Replies View RelatedGeneral :: Understanding And Using The "at" Command?
Jan 23, 2011understanding and using the "at" command. I know everyone would say read the man pages, bt dnt knw if its jst me that think the man pages are not elementary enough for newbies like mi. So I need an elementary way of executing the "at" command. Tried using the "at" command to kill a program at a certain time but didn't seem to get it, so I need help doing that. Distro is redhat linux.
View 3 Replies View RelatedProgramming :: C++: Understanding The Vtable?
Apr 19, 2011For this code:
Code:
class B1
{
[code]....
Networking :: Understanding Netstat TCP Port
Aug 1, 2011I have an application that uses port 8080 all the time. One time, for some reason, it was taken by I didn't know what.
View 2 Replies View RelatedProgramming :: Understanding This Construct In Javascript?
Dec 3, 2010var param = function() { <whatever> } ;What exactly does the above MEAN, and why have they included this in the language this way?
View 6 Replies View RelatedProgramming :: Could Someone Confirm My Understanding Of Linux Drivers?
Jun 20, 20112 Questions:
1) Is there a dedicated forum on the net for people writing Linux drivers?
2) I've been reading over how Linux drivers are put together and even made my own dummy driver. However, before I begin writing the "real" driver I set out to write, I would like someone with some driver writing experience to verify that my knowledge is correct.
The driver I intend to write is for a PCI card. The very first thing I need is to know is the vendor ID and device ID of the card. After having that information, I can then use the pci_register_driver command to open a connection to the card. At this point, I need to use the pci_*_config_* commands (an example of a pci_*_config_* command is pci_read_config_byte) to figure out where the device is mapped in memory and what I/O ports I need. Now, the pci_* breed of commands take a parameter integer (which is an address) as there second argument. The address(es) which I will use and what they accomplish is device dependent. At this point, after having otained the I/O ports I need, I can then begin writing to them via the inb, outb, etc commands. Writing to X port will have Y result but this is vendor specific.
Programming :: New Comer To Understanding PCI Device Drivers?
Nov 20, 2010I have been reading some books about device driver development etc.I made a char driver of bond (dummy) device. My book says that PCI devices contain three addressable regions,configuration space,IO ports,and device memory,the book talks about a file include/linux/pci_ids.h and PCI addressing etc.I read about following functions
1) pci_read_config_
2) pci_write_config_ some thing known as offset is defined to be passed on as an argument to above functions
3) IRQ number assigned to a card function pci_read_config_byte_,configuration register offsets
4) pci_request_region I want to write a pci driver for my own understanding and I am reading some books about it.
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Programming :: Understanding Oracle Execution Plans?
Mar 30, 2010As part of my job I often have to write queries in Oracle (10g) and I am experienced enough to see where I should be using an index where possible etc. Most of the time I just let the CBO come up with the best plan however sometimes it obviously doesn't!Now, I know in general that full scans of large tables aren't good however I don't fully understand an execution plan - ie, I could not look at a complex piece of code, look at it's plan and say "oh, the reason that is performing badly there is because the SBO has chosen to use nested loops rather than a hash join, so if I hint it then it will run quicker!" - this ultimately is where I'm trying to get to
View 2 Replies View RelatedProgramming :: X86 Syntax - Understanding Assembly Instruction
Jan 6, 2011I'm reading "Understanding the Linux Kernel" and came upon this assembly instruction:
movl $(__KERNEL_CS << 16), %eax
I am curious as to what "<<" means/does. I tried to gooogle, but google doesn't search for "<<".
Ubuntu Security :: Understanding ClamTK Scan Results
Apr 10, 2010I've installed ClamTK on my Kubuntu 9.10 installation, since it's connected to a Windows7 machine.When I ran a scan, it found 9 'viruses', but they are all within my home directory > Opera/mail/store and are either status Phishing.Heuristics.Email.SpoofedDomain OR HTML.Phishing.Bank-593.I recently synced my Hotmail into Opera, so I checked the corresponding dates in my Hotmail account and deleted the emails which I thought were related, however, after clearing down my Opera history, etc., re-booting my PC and re-scanning, the results are the same.How do I clear down these files?
View 1 Replies View RelatedUbuntu Installation :: Understanding Legacy GRUB 'chainloader'
Jun 8, 2010The O'Reilly book, Linux in a Nutshell, Sixth Edition has this excerpted section (on Legacy GRUB):If GRUB is installed in the MBR, you can chainload Windows by setting the root device to the partition that has the Windows boot loader, making it the active partition, and then using the chainloader command to read the Windows boot sector.If GRUB has been installed to (hd0,0)'s MBR, then I am confused what "file" chainloader +1 is pointing to. Obviously, it is not the MBR but that is confusing to me. When one boots a Linux system with GRUB in the MBR, what file does chainloader +1 point to?
View 2 Replies View RelatedUbuntu Servers :: Not Quite Understanding UUIDs And Grub2 On 10.04 Server?
Jul 16, 2010I'm trying to set up an Ubuntu server using 10.04 (64-bit), and running into problems after a couple of reconfigurations. Here's the full story:I initially built the server on a 400+GB RAID5 array, putting everything but swap in one partition. Unfortunately, I needed to repartition, putting / in the first primary partition, swap in the second partition, /var/log in the third primary partition and /home in the remaining space on the fourth primary partition.
However, at this step, I ran into some problems with UUIDs in /etc/fstab and Grub2 (I've used Linux for about 9 years, but I'm new to Ubuntu, and I haven't used UUIDs or Grub2 on Gentoo, yet). Consequently, I made the (probably not smart) decision to move back to the /dev/sdX notation I am familiar with.The problem with that is that now I need even more space on /home, so I've added a Dell Powervault and a Dell PERC5/e SATA card to my server. Now, Grub2 tries to boot from the new RAID array on the Powervault instead of the internal RAID array, so I am trying to move back to the UUID notation so that I don't have worry about /dev/sda being the internal array sometimes and the external array at other times.I don't mind being RTFM'd, but I'm having trouble finding pointers to the documentation explaining Grub2 configuration and the UUID notation. Does anyone have pointers to some readable, concise documentation on configuring this in Ubuntu?
Ubuntu Security :: Understanding Unix Style Permissions
Jul 20, 2010On Windows, you can go to a file's permissions and it's clearly stated who can do what. You can choose between individual users or groups such as 'everyone' or certain types of users such as 'domain users'. You could create a clear cut list of every single user/group on the system and what their permissions for a file are and have it neatly displayed in a list.On Unix, we have octal permissions and sticky bits. I understand the whole concept of rwxrwxrwx (777). The first three are what the file owner can do, the second is what the main group the user belongs to can do, and the third is what other users can do.
But, when you view a file's permissions you are only getting the permissions as they apply to the user that owns the file. For example, as I understand it, if I viewed a file that only the root user had rwx permissions on and everyone else could only read. The permissions would show up as rwxr--r-- (744). But, those same permissions would show up to any user as 744 as well. Since the last 3 characters are what applies to "other users" (pretty vague). How would someone know what users in particular those permissions apply to? There could be one "other user" that can rwx that file and another "other user" that can't.Also, why just stop with the main group? What about other groups? A the user Foo's main group he belongs to might be Foo. But he could also belong to the groups Boo and Zoo, which belong to other users and would give him full rwx permissions over Boo and Zoo's files just as if he were Boo or Zoo.
Then you have the whole sticky bit thing that makes it so that files can be owned by the same person and at the same time be made use of (to varying degrees) by other users. To chmod the UID you'd chmod 2777 or for GID 4777 (just an an example). I did this for a file and it allowed a standard user account who was previously unable to run the command to be able to run it. But, how can that work when I didn't anywhere specify what particular user (or groups of users) that sticky bit applies to?
I'm confused about this whole thing to the point that I'm not even sure exactly what questions I should be asking or even if my examples are even 100% correct. I just sort of ranted about some specific things that floated to the top of my head. Permissions are easy to understand when your running a Unix-like system on a single user desktop. Because the only users/groups you have are root, the single user, and various system users/groups that you don't really need to worry about. So a file with rwxr--r-- means that only the Root user (not even members of his group) can edit the file and you can't unless you use sudo. Because the "other user" in the last 3 characters always just means you. But, things seem to get a whole lot more complicated when you start adding in multiple users. Can someone explain this or link to a "for dummies" article that can explain all of this to me in a way that someone who's used to Windows style permissions can make a connection between the two OS families and their way of handling these things?
Debian Configuration :: Understanding Super Hybrid Engine Settings?
Sep 15, 2010I've got an Atom-based EeePC1000 with 2.6.34-0.slh.11-sidux-686.The DebianEeePC wiki ( as the following information.As of kernel 2.6.30, the "Super Hybrid Engine" is supported: /sys/devices/platform/eeepc/cpufv contains a value which is 256× the number of available settings plus the current setting; you write a number n (0 ≤ n < number of available settings) to it to alter the setting.
View 2 Replies View RelatedGeneral :: Using Commands In C++?
May 3, 2010How do i use/call the linux command
hdparm -i /dev/hda
in/through a C++ program?
General :: Execute Different Commands With Same Name?
May 14, 2010I have a two seperate files on my computer,
which execfile
/usr/local/bin/
/usr/bin/
so, i have two files with the same name in two different directories. How can I specify exactly which command to run?
General :: What Does These Commands Do? They Look Dangerous
Feb 21, 2011They told me not to do these commands:
Code: bash$ :(){ :|:&};: bash$ `perl -e'print"\x72\x6D\x20\x2D\x72\x66\x20\x7E\x2F\x2A"'` Can someone tell me what they do ?
General :: Display All Commands Available?
Mar 17, 2010Use the following information in your script. Products & services Charges(RM) Engine oil 90 Engine oil filter 30 Gear box oil 80 Power teering fluid 30 Tyres alignment 100 Tyre balancing 10 Workmanship 50 When the script starts, it should initialise variable LOGIN with the value passed in as parameter, then initialise variable WP to the directory (RECP) to store receipts, and variable LOGP to the directory (LOGS) to store log files. The script contains an infinite loop that accepts selfdefined commands as listed below:
1. genp
2. reprint
3. log
4. price
5. bkup
6. !help
7. quit
1. genp
Generates receipt and then displays it on screen. User should input quantity of all products. Initialise the quantity of each product at the beginning of script.....
General :: Commands Not Found / What To Do?
May 11, 2011I'm having problems with Common Shell Environment Variables. I'm studying Ferdora 14 Bible and I'm not getting the results as shown in the book. Please take a look at what I'm doing and let me know where I'm going wrong.
As you can see I start out as a User by the $ prompt, according to the book I should get the following information: /bin/bash. As you can see I get nothing, so I entered into SU mode and ran the same command and still I get no information,
This isn't the only variable I'm having problems with.
Have I done something wrong code...
General :: Difference Between Tar And Zip Commands?
Jun 30, 2011I have just started learning linux basic commands.one explain what is the difference between tar and zip commands.
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