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  • BASH: Checking for environment variables

    - by Hamza
    Hi folks, I am trying to check the value of an environment variable and depending on the value do certain things and it works fine as long as the variable is set. When it isn't though I get a whole bunch of errors (as BASH is trying to compare the string I specify with an undefined variable, I guess) I tried implementing an extra check to prevent it happening but no luck. The block of code I am using is: #!/bin/bash if [ -n $TESTVAR ] then if [ $TESTVAR == "x" ] then echo "foo" exit elif [ $TESTVAR == "y" ] then echo "bar" exit else echo "baz" exit fi else echo -e "TESTVAR not set\n" fi And this the output: $ export TESTVAR=x $ ./testenv.sh foo $ export TESTVAR=y $ ./testenv.sh bar $ export TESTVAR=q $ ./testenv.sh baz $ unset TESTVAR $ ./testenv.sh ./testenv.sh: line 5: [: ==: unary operator expected ./testenv.sh: line 9: [: ==: unary operator expected baz My question is, shouldn't 'unset TESTVAR' nullify it? It doesn't seem to be the case... Thanks.

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  • How to Implement Web Based Find File Database Via Text Search

    - by neversaint
    I have series of files like this: foo1.txt.gz foo2.txt.gz bar1.txt.gz ..etc.. and a tabular format file that describe those files: foo1 - Explain foo1 foo2 - Explain foo2 bar1 - Explain bar1 ..etc.. What I want to do is to have a website with a simple search bar and allow people to type foo1 or just foo and finally return the gzipped file(s) and the related explanation of the file(s). What's the best way to implement this and what kind of tools should I use. Sorry I am totally new in this area.

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  • filter log file by defining regexes

    - by fmpdmb
    I have some HUGE log files (50Mb; ~500K lines) I need to start filtering some of the crap out of. The log files are being produced using log4j and have the basic pattern of: [log-level] date-time class etc, etc log-message I'm looking for a way that I can identify a regex start and regex end (or something similar) that will filter out the matching entries from the file so I can more easily wade through these massive files. I'm sure I could write a java program to accomplish this task, but I thought I'd ask the community before going down that path. Thanks in advance.

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  • Parsing line with delimiter in Python

    - by neversaint
    I have lines of data which I want to parse. The data looks like this: a score=216 expect=1.05e-06 a score=180 expect=0.0394 What I want to do is to have a subroutine that parse them and return 2 values (score and expect) for each line. However this function of mine doesn't seem to work: def scoreEvalFromMaf(mafLines): for word in mafLines[0]: if word.startswith("score="): theScore = word.split('=')[1] theEval = word.split('=')[2] return [theScore, theEval] raise Exception("encountered an alignment without a score") Please advice what's the right way to do it?

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  • How to maipulate the shell output in php

    - by Mirage
    I am trying to write php script which does some shell functions like reporting. So i am starting with diskusage report I want in following format drive path ------------total-size --------free-space Nothing else My script is $output = shell_exec('df -h -T'); echo "<pre>$output</pre>"; and its ouput is like below Filesystem Type Size Used Avail Use% Mounted on /dev/sda6 ext3 92G 6.6G 81G 8% / none devtmpfs 3.9G 216K 3.9G 1% /dev none tmpfs 4.0G 176K 4.0G 1% /dev/shm none tmpfs 4.0G 1.1M 4.0G 1% /var/run none tmpfs 4.0G 0 4.0G 0% /var/lock none tmpfs 4.0G 0 4.0G 0% /lib/init/rw /dev/sdb1 ext3 459G 232G 204G 54% /media/Server /dev/sdb2 fuseblk 466G 254G 212G 55% /media/BACKUPS /dev/sda5 fuseblk 738G 243G 495G 33% /media/virtual_machines How can i convert that ouput into my forn\matted output

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  • are runtime linking library globals shared among plugins loaded with dlopen?

    - by conejoroy
    I've a C++ program that links at runtime with, lets say, mylib.so. then, the same program uses dlopen()/dlsym() to load a function from myplugin.so, dynamic library that in turn has dependencies to mylib.so. My question is: will the program AND the function in the plugin access the same globals defined in mydlib.so in the same memory area reserved for the program, or each will be assigned different, unrelated copies in its own memory space? if the latter is the default behaviour, is it possible to change that? Thanks in advance =)!

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  • selecting ppp of multiple interfaces

    - by Neeraj
    Hi everyone, I am currently having a hard time on getting the mobile broadband connection running on ubuntu 10.04(lucid lynx). I am using a USB modem and used wvdial to connect to the web It went like: Sending ATZ ... OK sending some more flags OK modem initialized connecting Local IP x.x.x.x Remote IP y.y.y.y Primary DNS z.z.z.z Secondary DNS a.a.a.a (Some more output) I tested this with invalid username to make sure it is really connected and i think it was connected as connection failed with invalid usernames. Now when I do a remote ping say 8.8.8.8 (Google DNS servers), the ping says unreachable I think this might be because the system may be using the ethernet to send packets which was indeed disconnected. So can anyone help me out with this. How can I select ppp as the interface to send packets or is there some other problem. A command line solution will be appreciated as my network manager applet doesnt works correctly. Any help is much much appreciated. -- thx

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  • What is the recommended way to package perl scripts for CPAN (and CorporatePAN)?

    - by szabgab
    Recently I looked at a module on CPAN that comes with a script to be installed which made me wonder. What is the recommended way to include a script in a package that should end up on the public CPAN and if there is any different recommendation for packages that would be released on an in-house CPAN server? The script starts like this: #!/usr/bin/perl eval 'exec /usr/bin/perl -S $0 ${1+"$@"}' if 0; # not running under some shell Two questions Do I understand correctly the eval part is unnecessary? That will be embedded by the CPAN client during installation and it will be very different when installing on Windows. What is the recommended sh-bang line? Would that be #!/usr/bin/env perl instead of the above?

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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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  • Are there any lint tools for C and C++ that check formatting?

    - by Nathan Fellman
    I have a codebase that is touched by many people. While most people make an effort to keep the code nicely formatted (e.g. consistent indentation and use of braces), some don't, and even those that do can't always do it because we all use different editors, so settings like spaces vs. tabs are different. Is there any standard lint tool that checks that code is properly formatted, but doesn't actually change it (like indent but that returns only errors and warnings)? While this question could be answered generally, my focus is on C and C++, because that's what this project is written in.

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  • Preventing FIN_WAIT2 when closing socket

    - by patrickvacek
    I have a server program that connects to another program via a given socket, and in certain cases I need to close the connection and almost immediately re-open it on the same socket. This by and large works, except that I have to wait exactly one minute for the socket to reset. In the meantime, netstat indicates that the server sees the socket in FIN_WAIT2 and the client sees it as CLOSE_WAIT. I'm already using SO_REUSEADDR, which I thought would prevent the wait, but that isn't doing the trick. Setting SO_LINGER to zero also does not help. What else can I do to resolve this? Here are the relevant code snippets: SetUpSocket() { // Set up the socket and listen for a connection from the exelerate client. // Open a TCP/IP socket. m_baseSock = socket(PF_INET, SOCK_STREAM, IPPROTO_IP); if (m_baseSock < 0) { return XERROR; } // Set the socket options to reuse local addresses. int flag = 1; if (setsockopt(m_baseSock, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag)) == -1) { return XERROR; } // Set the socket options to prevent lingering after closing the socket. //~ linger li = {1,0}; //~ if (setsockopt(m_baseSock, SOL_SOCKET, SO_LINGER, &li, sizeof(li)) == -1) //~ { //~ return XERROR; //~ } // Bind the socket to the address of the current host and our given port. struct sockaddr_in addr; memset(&addr, 0, sizeof(addr)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = INADDR_ANY; addr.sin_port = htons(m_port); if (bind(m_baseSock, (struct sockaddr*)&addr, sizeof(addr)) != 0) { return XERROR; } // Tell the socket to listen for a connection from client. if (listen(m_baseSock, 4) != 0) { return XERROR; } return XSUCCESS; } ConnectSocket() { // Add the socket to a file descriptor set. fd_set readfds; FD_ZERO(&readfds); FD_SET(m_baseSock, &readfds); // Set timeout to ten seconds. Plenty of time. struct timeval timeout; timeout.tv_sec = 10; timeout.tv_usec = 0; // Check to see if the socket is ready for reading. int numReady = select(m_baseSock + 1, &readfds, NULL, NULL, &timeout); if (numReady > 0) { int flags = fcntl(m_baseSock, F_GETFL, 0); fcntl(m_baseSock, flags | O_NONBLOCK, 1); // Wait for a connection attempt from the client. Do not block - we shouldn't // need to since we just selected. m_connectedSock = accept(m_baseSock, NULL, NULL); if (m_connectedSock > 0) { m_failedSend = false; m_logout = false; // Spawn a thread to accept commands from client. CreateThread(&m_controlThread, ControlThread, (void *)&m_connectedSock); return XSUCCESS; } } return XERROR; } ControlThread(void *arg) { // Get the socket from the argument. socket sock = *((socket*)arg); while (true) { // Add the socket to a file descriptor set. fd_set readfds; FD_ZERO(&readfds); FD_SET(sock, &readfds); // Set timeout to ten seconds. Plenty of time. struct timeval timeout; timeout.tv_sec = 10; timeout.tv_usec = 0; // Check if there is any readable data on the socket. int num_ready = select(sock + 1, &readfds, NULL, NULL, &timeout); if (num_ready < 0) { return NULL; } // If there is data, read it. else if (num_ready > 0) { // Check the read buffer. xuint8 buf[128]; ssize_t size_read = recv(sock, buf, sizeof(buf)); if (size_read > 0) { // Get the message out of the buffer. char msg = *buf; if (msg == CONNECTED) { // Do some things... } // If we get the log-out message, log out. else if (msg == LOGOUT) { return NULL; } } } } // while return NULL; } ~Server() { // Close the sockets. if (m_baseSock != SOCKET_ERROR) { close(m_baseSock); m_baseSock = SOCKET_ERROR; } if (m_connectedSock != SOCKET_ERROR) { close(m_connectedSock); m_connectedSock = SOCKET_ERROR; } } SOCKET_ERROR is equal to -1. The server object gets destroyed, at which point the connection should close, and then recreated, at which point the SetUpSocket() and ConnectSocket() routines are called. So why do I have to wait a minute for the socket to clear? Any ideas would be appreaciated.

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  • Getting error that the database is locked when refreshing the page

    - by acidzombie24
    The title is a joke. However it is serious as far as my app is concerned. I am running apache with mod mono and my asp.net app is using mono sqlite as its db. When i refresh the page twice i get the DB is locked error. The folder it is in is chmod 777. The webapp is creating sqlite.db and sqlite.db-journal but it doesnt seem to be able to delete the journal. i'm confused. What permissions do i need to set these? i tried precreating the files using 777 and had no luck.

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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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  • symlink and sudo executable

    - by CodeMedic
    If I have the below sudoers entry usera ALL=(userb) NOPASSWD: /home/userc/bin/executable-file usera ALL=(userb) NOPASSWD: /home/userc/bin/link-to-another-executable-file When I log-on as usera and try running the below commands, it works sudo -u userb /home/userc/bin/executable-file but NOT the one below. sudo -u userb /home/userc/bin/link-to-another-executable-file Sorry, user usera is not allowed to execute '/home/userc/bin/link-to-another-executable-file' as userb on hostname. Any ideas?

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  • Is there a way to find a specific file and then change into the directory containing it in one go?

    - by bergyman
    I'm looking for a way to find what I know will be a unique file, and then change into the directory containing that file. Something along the lines of: find . -name 'Subscription.java' | xargs cd Or: find . -name 'Subscription.java' -exec cd {} \; I know this won't work because it's both trying to cd supplying the entire absolute path, which contains the file, and also because xargs can't do any built in shell commands...but you get the point of what I want to accomplish.

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  • Modify bash variables with sed

    - by Alexander Cska
    I am trying to modify a number of environmental variables containing predefined compiler flags. To do so, I tried using a bash loop that goes over all environmental variables listed with "env". for i in $(env | grep ipo | awk 'BEGIN {FS="="} ; { print $1 } ' ) do echo $(sed -e "s/-ipo/ / ; s/-axAVX/ /" <<< $i) done This is not working since the loop variable $i contains just the name of the environmental variable stored as a character string. I tried searching a method to convert a string into a variable but things started becoming unnecessary complicated. The basic problem is how to properly supply the environmental variable itself to sed. Any ideas how to properly modify my script are welcome. Thanks, Alex

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  • Dynamic loaded libraries and shared global symbols

    - by phlipsy
    Since I observed some strange behavior of global variables in my dynamically loaded libraries, I wrote the following test. At first we need a statically linked library: The header test.hpp #ifndef __BASE_HPP #define __BASE_HPP #include <iostream> class test { private: int value; public: test(int value) : value(value) { std::cout << "test::test(int) : value = " << value << std::endl; } ~test() { std::cout << "test::~test() : value = " << value << std::endl; } int get_value() const { return value; } void set_value(int new_value) { value = new_value; } }; extern test global_test; #endif // __BASE_HPP and the source test.cpp #include "base.hpp" test global_test = test(1); Then I wrote a dynamically loaded library: library.cpp #include "base.hpp" extern "C" { test* get_global_test() { return &global_test; } } and a client program loading this library: client.cpp #include <iostream> #include <dlfcn.h> #include "base.hpp" typedef test* get_global_test_t(); int main() { global_test.set_value(2); // global_test from libbase.a std::cout << "client: " << global_test.get_value() << std::endl; void* handle = dlopen("./liblibrary.so", RTLD_LAZY); if (handle == NULL) { std::cout << dlerror() << std::endl; return 1; } get_global_test_t* get_global_test = NULL; void* func = dlsym(handle, "get_global_test"); if (func == NULL) { std::cout << dlerror() << std::endl; return 1; } else get_global_test = reinterpret_cast<get_global_test_t*>(func); test* t = get_global_test(); // global_test from liblibrary.so std::cout << "liblibrary.so: " << t->get_value() << std::endl; std::cout << "client: " << global_test.get_value() << std::endl; dlclose(handle); return 0; } Now I compile the statically loaded library with g++ -Wall -g -c base.cpp ar rcs libbase.a base.o the dynamically loaded library g++ -Wall -g -fPIC -shared library.cpp libbase.a -o liblibrary.so and the client g++ -Wall -g -ldl client.cpp libbase.a -o client Now I observe: The client and the dynamically loaded library possess a different version of the variable global_test. But in my project I'm using cmake. The build script looks like this: CMAKE_MINIMUM_REQUIRED(VERSION 2.6) PROJECT(globaltest) ADD_LIBRARY(base STATIC base.cpp) ADD_LIBRARY(library MODULE library.cpp) TARGET_LINK_LIBRARIES(library base) ADD_EXECUTABLE(client client.cpp) TARGET_LINK_LIBRARIES(client base dl) analyzing the created makefiles I found that cmake builds the client with g++ -Wall -g -ldl -rdynamic client.cpp libbase.a -o client This ends up in a slightly different but fatal behavior: The global_test of the client and the dynamically loaded library are the same but will be destroyed two times at the end of the program. Am I using cmake in a wrong way? Is it possible that the client and the dynamically loaded library use the same global_test but without this double destruction problem?

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  • Shell script to count files, then remove oldest files

    - by Nic Hubbard
    I am new to shell scripting, so I need some help here. I have a directory that fills up with backups. If I have more than 10 backup files, I would like to remove the oldest files, so that the 10 newest backup files are the only ones that are left. So far, I know how to count the files, which seems easy enough, but how do I then remove the oldest files, if the count is over 10? if [ls /backups | wc -l > 10] then echo "More than 10" fi

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  • Question about Modal Dialog in Gtk application

    - by michael
    Hi, In Gtk application, there is 1 main loop which listens for events (e.g. mouse click, keyboard, etc). And when a modal dialog popup, the main loop is blocked until user clicks 'OK' in the dialog, right? (i.e. nothing will happen when user clicks on the main window). Is that correct? My question is how can firefox did its modal dialog so that it can: 1. when 1 have 2 Firefox windows 2. one of them has a modal dialog 3. other one is still interactive If both window shares the same gtk main loop, how is that possible? Please help me understanding this. Thank you.

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  • Ubuntu's file-roller problem 5010. "Cannot open display"

    - by Denis
    Hello everybody! I use "file-roller" to manage with archieves on my Ubuntu. But it fails on running without user interface(just teminal). The error is shown below. ** (file-roller:5453): CRITICAL **: Failed to parse arguments: Cannot open display: How can I prevent file-roller from using GUI or can you recommend me any other archieve manager I can use from terminal. It would be perfect, if this manager can handle as much formats as it is possible.

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  • Grep in XML file

    - by nishant
    I have to find some patters from a XML file, but i am unable to do it. <field> <uniqueid>account </uniqueod> <tableid>afs</tableid> </field> <field> <uniqueid>address</uniqueod> <tableid>afs</tableid> </field> what i have to do is to search the entries between these two fields and redirect them to a file.txt.and output should be such that uniqueid tableid uniqueid tableid i.e. for each uniqueid tableid should be printed along with it. The entries can be different or same. Guys help me out...

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