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  • How to store and echo multiple lines elegantly in bash?

    - by EmpireJones
    I'm trying to capture a block of text into a variable, with newlines maintained, then echo it. However, the newlines don't seemed to be maintained when I am either capturing the text or displaying it. Any ideas regarding how I can accomplish this? Example: #!/bin/bash read -d '' my_var <<"BLOCK" this is a test BLOCK echo $my_var Output: this is a test Desired output: this is a test

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  • Setting up separate ctags db's for C/C++ standard libs, boost, and third party libs

    - by Robert S. Barnes
    I want to set up separate ctags databases for various libraries in /usr/include/ for use with OmniCppComplete. The idea is to be able to pull in only the libraries needed for a particular project in the target language - C or C++. For example, I'd like to have one database for the standard C libraries, one for system libraries that might be used by either C or C++ programs ( sockets / networking comes to mind ) one for the standard C++ libs / STL / Boost, and then other databases for various third party libraries such as QT or glib. Then I could pull something in simply by typing set tags+= ~/.vim/somelib.tags in vim. I assume that everything related to the C++ stdlib and STL are in the /usr/include/c++ and that Boost is all in /usr/include/boost. Unfortunately it seems that the standard C libs and system libs are just kind of dumped directly into /usr/include/ with a variety of other stuff. How can I get a list of which files and directories belong to which libs? I'm on Ubuntu 8.04.

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  • Can not set password for mysql server in cent os 6.2

    - by HarshanaD
    I have installed mysql and then mysql-server. Then i start the mysql demon and follow below steps, # chkconfig --level 2345 mysqld on # mysqladmin -u root password testpassword But i can not set the password because it gives me the below error, Access denied for user root@localhost (using password: no) I logged in as root user and perform those steps. I even uninstalled mysql server and reinstalled but same problem occurred.

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  • Easily measure elapsed time

    - by hap497
    I am trying to use time() to measure various points of my program. What I don't understand is why the values in the before and after are the same? I understand this is not the best way to profile my program, I just want to see how long something take. printf("**MyProgram::before time= %ld\n", time(NULL)); doSomthing(); doSomthingLong(); printf("**MyProgram::after time= %ld\n", time(NULL)); I have tried: struct timeval diff, startTV, endTV; gettimeofday(&startTV, NULL); doSomething(); doSomethingLong(); gettimeofday(&endTV, NULL); timersub(&endTV, &startTV, &diff); printf("**time taken = %ld %ld\n", diff.tv_sec, diff.tv_usec); How do I read a result of **time taken = 0 26339? Does that mean 26,339 nanoseconds = 26.3 msec? What about **time taken = 4 45025, does that mean 4 seconds and 25 msec?

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  • Howto Plot "Reverse" Cumulative Frequency Graph With ECDF

    - by neversaint
    I have no problem plotting the following cumulative frequency graph plot like this. library(Hmisc) pre.test <- rnorm(100,50,10) post.test <- rnorm(100,55,10) x <- c(pre.test, post.test) g <- c(rep('Pre',length(pre.test)),rep('Post',length(post.test))) Ecdf(x, group=g, what="f", xlab='Test Results', label.curves=list(keys=1:2)) But I want to show the graph in forms of the "reverse" cumulative frequency of values x ? (i.e. something equivalent to what="1-f"). Is there a way to do it? Other suggestions in R other than using Hmisc are also very much welcomed.

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  • Bash PATH: How long is too long?

    - by ajwood
    Hi, I'm currently designing a software quarantine pattern to use on Ubuntu. I'm not sure how standard "quarantine" is in this context, so here is what I hope to accomplish... Inside a particular quarantine is all of the stuff one needs to run an application (bin, share, lib, etc.). Ideally, the quarantine has no leaks, which means it's not relying on any code outside of itself on the system. A quarantine can be defined as a set of executables (and some environment settings needed to make them run). I think it will be beneficial to separate the built packages enough such that upgrading to a newer version of the quarantine won't require rebuilding the whole thing. I'll be able to update just a few packages, and then the new quarantine can use some of old parts and some of the new parts. One issue I'm wondering about is the environment variables I'll be setting up to use a particular quarantines. Is there a hard limit on how big PATH can be? (either in number of characters, or in the number of directories it contains) Might a path be so long that it affects performance? Thanks very much, Andrew p.s. Any other wisdom that might help my design would be greatly appreciated :)

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  • c, pass awk syntax as argument to execl

    - by Skuja
    I want to run following command in c to read systems cpu and memory usage: ps aux|awk 'NR > 0 { cpu +=$3; ram+=$4 }; END {print cpu,ram}' I am trying to pass it to execl command and after that read its output: execl("/bin/ps", "/bin/ps", "aux|awk", "'NR > 0 { cpu +=$3; ram+=$4 }; END {print cpu,ram}'",(char *) 0); but in terminal i am getting following error: ERROR: Unsupported option (BSD syntax) I would like to know how to properly pass awk as argument to execl?

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  • ZeroMQ REQ/REP on ipc:// and concurrency

    - by Metiu
    I implemented a JSON-RPC server using a REQ/REP 0MQ ipc:// socket and I'm experiencing strange behavior which I suspect is due to the fact that the ipc:// underlying unix socket is not a real socket, but rather a single pipe. From the documentation, one has to enforce strict zmq_send()/zmq_recv() alternation, otherwise the out-of-order zmq_send() will return an error. However, I expected the enforcement to be per-client, not per-socket. Of course with a Unix socket there is just one pipeline from multiple clients to the server, so the server won't know who it is talking with. Two clients could zmq_send() simultaneously and the server would see this as an alternation violation. The sequence could be: ClientA: zmq_send() ClientB: zmq_send() : will it block until the other send/receive completes? will it return -1? (I suspect it will with ipc:// due to inherent low-level problems, but with TCP it could distinguish the two clients) ClientA: zmq_recv() ClientB: zmq_recv() so what about tcp:// sockets? Will it work concurrently? Should I use some other locking mechanism to work around this?

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  • How to implement/debug a sensor driver in ANDROID

    - by CVS-2600Hertz-wordpress-com
    Does anyone know of a walk-through or any examples of any code to setup sensors in android. I have the drivers available to me. Also i have implemented the sensors library as instructed in the Android-Reference along the sensors.h template. I am still unable to get any response at the apps level. How do i trace this issue? what might be the problem? Thanks in advance UPDATE: Jorgesys's link below points to a great APP to test if the sensor drivers are functioning properly or not. Not that i know they are not functioning, Any ideas of on where to dig??...

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  • EXMPP Buillding Error

    - by pradeepchhetri
    I am trying to install exmpp but while building i am getting the following error: exmpp_tls_openssl.c: In function 'init_library': exmpp_tls_openssl.c:622: error: 'SSL_OP_NO_TICKET' undeclared (first use in this function) exmpp_tls_openssl.c:622: error: (Each undeclared identifier is reported only once exmpp_tls_openssl.c:622: error: for each function it appears in.) make[2]: *** [exmpp_tls_openssl_la-exmpp_tls_openssl.lo] Error 1 I have openssl-dev and openssl both installed. Can someone please tell me what is the problem.

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  • How can I quickly sum all numbers in a file?

    - by Mark Roberts
    I have a file which contains several thousand numbers, each on it's own line: 34 42 11 6 2 99 ... I'm looking to write a script which will print the sum of all numbers in the file. I've got a solution, but it's not very efficient. (It takes several minutes to run.) I'm looking for a more efficient solution. Any suggestions?

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  • CVS in cmd/gui works only the third time I run a command.

    - by Somebody still uses you MS-DOS
    I'm using CVS in the command line. I'm in my repository folder. When I call a CVS command, I get... cvs [log aborted]: unrecognized auth response from localhost: -f [pserver aborted]: /opt/cvs/XXXXXX: no such repository ...2 times. The third time I run the command, it works with no problems. I tried to use a GUI client (CrossVC) and the same problem occurs. I tried inside gVim and Vim using VCSCommand and I'm having the same issues as well. I've tested with different times between each command, but I still have the same problems. I'm using a CVS configuration with stunnel. Why am I having problem with this setup? Why every time just the third time that I try to run the command that actually works?

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  • Passing enums to functions in C++

    - by rocknroll
    Hi all, I have a header file with all the enums listed (#ifndef #define #endif construct has been used to avoid multiple inclusion of the file) that I use in multiple cpp files in my application.One of the enums in the files is enum StatusSubsystem {ENABLED,INCORRECT_FRAME,INVALID_DATA,DISABLED}; There are functions in the application delcared as ShowStatus(const StatusSubsystem&); Earlier in the application when I made calls to the above function like ShowStatus(INCORRECT_FRAME); my application used to compile perfectly. But after some code was added The compilation halts giving the following error: File.cpp:71: error: invalid conversion from `int' to `StatusSubsystem' File.cpp:71: error: initializing argument 1 of `void Class::ShowStatus(const StatusSubsystem&) I checked the code for any conflicting enums in the new code and it looked fine. My Question is what is wrong with the function call that compiler shows as erroneous? For your reference the function definition is: void Class::ShowStatus(const StatusSubsystem& eStatus) { QPalette palette; mStatus=eStatus;//store current Communication status of system if(eStatus==DISABLED) { //select red color for label, if it is to be shown disabled palette.setColor(QPalette::Window,QColor(Qt::red)); mLabel->setText("SYSTEM"); } else if(eStatus==ENABLED) { //select green color for label,if it is to be shown enabled palette.setColor(QPalette::Window,QColor(Qt::green)); mLabel->setText("SYSTEM"); } else if(eStatus==INCORRECT_FRAME) { //select yellow color for label,to show that it is sending incorrect frames palette.setColor(QPalette::Window,QColor(Qt::yellow)); mLabel->setText("SYSTEM(I)"); } //Set the color on the Label mLabel->setPalette(palette); } A strange side effect of this situation is it compiles when I cast all the calls to ShowStatus() as ShowStatus((StatusSubsystem)INCORRECT_FRAME); Though this removes any compilation error, but a strange thing happens. Though I make call to INCORRECT_FRAME above but in function definition it matches with ENABLED. How on earth is that possible? Its like while passing INCORRECT_FRAME by reference, it magically converts to ENABLED, which should be impossible. This is driving me nuts. Can you find any flaw in what I am doing? or is it something else? The application is made using C++,Qt-4.2.1 on RHEL4. Thanks.

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  • Are there any platforms where using structure copy on an fd_set (for select() or pselect()) causes p

    - by Jonathan Leffler
    The select() and pselect() system calls modify their arguments (the 'struct fd_set *' arguments), so the input value tells the system which file descriptors to check and the return values tell the programmer which file descriptors are currently usable. If you are going to call them repeatedly for the same set of file descriptors, you need to ensure that you have a fresh copy of the descriptors for each call. The obvious way to do that is to use a structure copy: struct fd_set ref_set_rd; struct fd_set ref_set_wr; struct fd_set ref_set_er; ... ...code to set the reference fd_set_xx values... ... while (!done) { struct fd_set act_set_rd = ref_set_rd; struct fd_set act_set_wr = ref_set_wr; struct fd_set act_set_er = ref_set_er; int bits_set = select(max_fd, &act_set_rd, &act_set_wr, &act_set_er, &timeout); if (bits_set > 0) { ...process the output values of act_set_xx... } } My question: Are there any platforms where it is not safe to do a structure copy of the struct fd_set values as shown? I'm concerned lest there be hidden memory allocation or anything unexpected like that. (There are macros/functions FD_SET(), FD_CLR(), FD_ZERO() and FD_ISSET() to mask the internals from the application.) I can see that MacOS X (Darwin) is safe; other BSD-based systems are likely to be safe, therefore. You can help by documenting other systems that you know are safe in your answers. (I do have minor concerns about how well the struct fd_set would work with more than 8192 open file descriptors - the default maximum number of open files is only 256, but the maximum number is 'unlimited'. Also, since the structures are 1 KB, the copying code is not dreadfully efficient, but then running through a list of file descriptors to recreate the input mask on each cycle is not necessarily efficient either. Maybe you can't do select() when you have that many file descriptors open, though that is when you are most likely to need the functionality.) There's a related SO question - asking about 'poll() vs select()' which addresses a different set of issues from this question.

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  • Regarding Shell variable

    - by arav
    I need to call another shell script testarg.sh within my main script. This script testarg.sh has arguments ARG1 ,ARG2, ARG3. I need to call up the below way ./testarg.sh -ARG1 -ARG2 -ARG3 ARG1 and ARG3 argument Variables are mandatory ones. If its not passed to the main script then i quit. ARG2 is an optional one. If the ARG2 variable is not set with value or it's not defined then i need not pass it from main script.So i need to call up the below way ./testarg.sh -ARG1 -ARG3 If the value exist for the ARG2 Varibale then i need to call the below way ./testarg.sh -ARG1 -ARG2 -ARG3 Do i need to have a if else statement for checking the ARG2 variable is empty or null. Is there any other way to do it.

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  • Perl standard input with argument inside Bash

    - by neversaint
    I want to have such pipe in bash #! /usr/bin/bash cut -f1,2 file1.txt | myperl.pl foo | sort -u Now in myperl.pl it has content like this my $argv = $ARG[0] || "foo"; while (<>) { chomp; if ($argv eq "foo") { # do something with $_ } else { # do another } } But why the Perl script can't recognize the parameter passed through bash? Namely the code break with this message: Can't open foo: No such file or directory at myperl.pl line 15. What the right way to do it so that my Perl script can receive standard input and parameter at the same time?

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  • In BASH how can i find my system on active internet interface, what is the upload speed?

    - by YumYumYum
    I am trying to write an TUI bandwidth trace application which on query can instantly tell me, that my download and upload speed is XXXX. I have figured out that download i can use with wget and parse it using BASH, but how do i get the upload speed? Example of download parse method: 1) Remote download : wget http://x.x.com:7007/files/software/vnc.zip Length: 1594344 (1.5M) [application/zip] Saving to: `vnc.zip' 100%[==================================================================>] 1,594,344 573K/s in 2.7s 2012-03-24 11:35:22 (573 KB/s) - `vnc.zip' saved [1594344/1594344] 2) Local download tells Length: 1594344 (1.5M) [application/zip] Saving to: `vnc.zip' 100%[==================================================================>] 1,594,344 --.-K/s in 0.1s 2012-03-24 06:43:04 (11.4 MB/s) - `vnc.zip' saved [1594344/1594344]

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  • Would it be simply better to use the system's functions rather than use the language?

    - by Nullw0rm
    There are many scenarios where I've questioned PHP's performance with some of its functions, and whether I should build a complex class to handle specific things using its seemingly slow tools. For example, Complex regular expressions with sed and processing with awk would seemingly be exponential in performance rather than making PHP's regular expression and seemingly excessive functions parse and in time manage to finish it. If I were to do a lot of network tasks such as MX lookups/DIGging/retrieving simultaneously I would rather pass it via system() and let the OS handle it itself. There are simply too many functions in PHP, that are inefficient and result in slow pages or can be handled easier by the OS. What are your opinions? Do you think I should do the hard work with the OS in its own/custom functions?

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  • SOLVED - UBIFS partition mounting at startup [closed]

    - by Bartlomiej Grzeskowiak
    [SOLVED] - add ubi.mtd=volume_name to bootargs in uboot I want to mount UBIFS partition via /etc/fstab at startup. I created UBIFS and Volume: # ubiformat /dev/mtdX # ubiattach -p /dev/mtdX # ubimkvol /dev/ubi0 -N volume_name -s 64MiB # ubiupdatevol /dev/ubi0_0 /path/to/ubifs.img # mount -t ubifs ubi0:volume_name /mount/point but after reboot this line in etc/fstab doesn't work: ubi0:volume_name /mnt/user ubifs defaults 0 0 There is no fs mounted in /mnt/user. Also when I try to call mount -a: mount: mounting ubi0:volume_name on /mnt/user failed: No such device There are no ubi0,ubi0_0 in /dev. I also don't see any UBI calls in dmesg like here: UBIFS boot error

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