Search Results

Search found 4938 results on 198 pages for 'unix timestamp'.

Page 75/198 | < Previous Page | 71 72 73 74 75 76 77 78 79 80 81 82  | Next Page >

  • after dup2, stream still contains old contents?

    - by BobTurbo
    so if I do: dup2(0, backup); // backup stdin dup2(somefile, 0); // somefile has four lines of content fgets(...stdin); // consume one line fgets(....stdin); // consume two lines dup2(backup, 0); // switch stdin back to keyboard I am finding at this point.. stdin still contains the two lines I haven't consumed. Why is that? Because there is just one buffer no matter how many times you redirect? How do I get rid of the two lines left but still remember where I was in the somefile stream when I want to go back to it?

    Read the article

  • What is the point of having a key_t if what will be the key to access shared memory is the return value of shmget()?

    - by devoured elysium
    When using shared memory, why should we care about creating a key key_t ftok(const char *path, int id); in the following bit of code? key_t key; int shmid; key = ftok("/home/beej/somefile3", 'R'); shmid = shmget(key, 1024, 0644 | IPC_CREAT); From what I've come to understand, what is needed to access a given shared memory is the shmid, not the key. Or am I wrong? If what we need is the shmid, what is the point in not just creating a random key every time? Edit @link text one can read: What about this key nonsense? How do we create one? Well, since the type key_t is actually just a long, you can use any number you want. But what if you hard-code the number and some other unrelated program hardcodes the same number but wants another queue? The solution is to use the ftok() function which generates a key from two arguments. Reading this, it gives me the impression that what one needs to attach to a shared-memory block is the key. But this isn't true, is it? Thanks

    Read the article

  • grep value inside a variable pointing to other variable

    - by Joice
    using : ksh *abc = 1 efg = 2 hgd = 3 not known to me * say if i have Value="abc efg hgd" abc efg hgd all contains some value which i dnt know. Now I want to grep the value contained inside abc. like for i in $Value do grep "echo $(($((echo $i | cut -d'|' -f2))))" done this grep should look for the value inside abc efg hgd grep 1 grep 2 grep 3

    Read the article

  • Speeding up a group by date query on a big table in postgres

    - by zaius
    I've got a table with around 20 million rows. For arguments sake, lets say there are two columns in the table - an id and a timestamp. I'm trying to get a count of the number of items per day. Here's what I have at the moment. SELECT DATE(timestamp) AS day, COUNT(*) FROM actions WHERE DATE(timestamp) >= '20100101' AND DATE(timestamp) < '20110101' GROUP BY day; Without any indices, this takes about a 30s to run on my machine. Here's the explain analyze output: GroupAggregate (cost=675462.78..676813.42 rows=46532 width=8) (actual time=24467.404..32417.643 rows=346 loops=1) -> Sort (cost=675462.78..675680.34 rows=87021 width=8) (actual time=24466.730..29071.438 rows=17321121 loops=1) Sort Key: (date("timestamp")) Sort Method: external merge Disk: 372496kB -> Seq Scan on actions (cost=0.00..667133.11 rows=87021 width=8) (actual time=1.981..12368.186 rows=17321121 loops=1) Filter: ((date("timestamp") >= '2010-01-01'::date) AND (date("timestamp") < '2011-01-01'::date)) Total runtime: 32447.762 ms Since I'm seeing a sequential scan, I tried to index on the date aggregate CREATE INDEX ON actions (DATE(timestamp)); Which cuts the speed by about 50%. HashAggregate (cost=796710.64..796716.19 rows=370 width=8) (actual time=17038.503..17038.590 rows=346 loops=1) -> Seq Scan on actions (cost=0.00..710202.27 rows=17301674 width=8) (actual time=1.745..12080.877 rows=17321121 loops=1) Filter: ((date("timestamp") >= '2010-01-01'::date) AND (date("timestamp") < '2011-01-01'::date)) Total runtime: 17038.663 ms I'm new to this whole query-optimization business, and I have no idea what to do next. Any clues how I could get this query running faster?

    Read the article

  • Symlinking folders in bash

    - by user343223
    I want a folder /public_html to symlink to /current/app/webroot, both are in the same directory I have tried ln -s public_html current/app/webroot amongst other things, but no joy so far. Any ideas?

    Read the article

  • malloc in kernel

    - by yoavstr
    when i try to malloc at kernel mod i get screamed by the compiler : res=(ListNode*)malloc(sizeof(ListNode)); and the compiler is screaming : /root/ex3/ex3mod.c:491: error: implicit declaration of function ‘malloc’ what should i do ?

    Read the article

  • how to send text to a process in a shell script?

    - by Martin
    So I have a Linux program that runs in a while(true) loop, which waits for user input, process it and print result to stdout. I want to write a shell script that open this program, feed it lines from a txt file, one line at a time and save the program output for each line to a file. So I want to know if there is any command for: - open a program - send text to a process - receive output from that program Many thanks.

    Read the article

  • Passing partial arguments in tcshell

    - by R S
    Hey, I'm writing a shell script (tcsh) that is supposed to received 3 parameters or more. The first 3 are to be passed to a program, and the rest are supposed to be passed to another program. All in all the script should look something like: ./first_program $1 $2 $3 ./second program [fourth or more] The problem is that I don't know how to do the latter - pass all parameters that are after the third.

    Read the article

  • How can I measure my (SAMP) server's bandwidth usage?

    - by enkrates
    I'm running a Solaris server to serve PHP through Apache. What tools can I use to measure the bandwidth my server is currently using? I use Google analytics to measure traffic, but as far as I know, it ignores file size. I have a rough idea of the average size of the pages I serve, and can do a back-of-the-envelope calculation of my bandwidth usage by multiplying page views (from Google) by average page size, but I'm looking for a solution that is more rigorous and exact. Also, I'm not trying to throttle anything, or implement usage caps or anything like that. I'd just like to measure the bandwidth usage, so I know what it is. An example of what I'm after is the usage meter that Slicehost provides in their admin website for their users. They tell me (for another site I run) how much bandwidth I've used each month and also divide the usage for uploading and downloading. So, it seems like this data can be measured, and I'd like to be able to do it myself. To put it simply, what is the conventional method for measuring the bandwidth usage of my server?

    Read the article

  • C Allocating Two Dimensional Arrays

    - by Jacob
    I am trying to allocate a 2D dimension array of File Descriptors... So I would need something like this fd[0][0] fd[0][1] I have coded so far: void allocateMemory(int row, int col, int ***myPipes){ int i = 0,i2 = 0; myPipes = (int**)malloc(row * sizeof(int*)); for(i = 0; i < row;i++){ myPipes[i] = (int*)malloc(col * sizeof(int)); } } How can I set it all too zeros right now I keep getting a seg fault when I try to assign a value... Thanks

    Read the article

  • Debugging errors in c++

    - by user1513323
    I was working on a program that printed out the word count, character count and line count depending on the user's input. But I keep getting these error that are completely unknown to me. I was wondering if anyone could help. ** I've changed it from previous mistakes and am still receiving errors. Sorry I'm new to C++. The errors I got were filestat.cpp:47: error: ‘line’ was not declared in this scope filestat.cpp: In function ‘int wc(std::string)’: filestat.cpp:55: error: ‘line’ was not declared in this scope filestat.cpp: In function ‘int cc(std::string)’: filestat.cpp:67: error: ‘line’ was not declared in this scope #include<iostream> #include<fstream> #include<string> using namespace std; int lc(string fname); int wc(string fname); int cc(string fname); int main(){ string fname,line,command; ifstream ifs; int i; while(true){ cout<<"---- Enter a file name : "; if(getline(cin,line)){ if(line.length()== 4 && line.compare("exit")== 0){ cout<<"Exiting"; exit(0); }else{ string command = line.substr(0,2); fname= line.substr(4, line.length() -5); if( ifs.fail()){ ifs.open(fname.c_str()); cerr<< "File not found" <<fname <<endl; ifs.clear(); }else{ if(command.compare("lc")){ lc(fname); }else if (command.compare("wc")){ wc(fname); }else if(command.compare("cc")){ cc(fname); }else cout<<"Command unknown. "; } } } } return 0; } int lc(string fname){ int count; while(getline(fname, line)){ count++; } cout<<"Number of lines: "<<count ; } int wc(string fname){ int count; while(getline(fname, line)){ int pos=line.find_first_of("\n\t ",0); while(pos =! string::npos){ int length=line.length(); line = line.substr(pos+1, length - pos); count++; } } cout<< "Number of words: " <<count; } int cc(string fname){ int count; while(getline(fname, line)){ count = count + line.length(); } cout<< "Number of words: " <<count; }

    Read the article

  • How to find out how namespace got polluted?

    - by dehmann
    Consider the following little piece of code: // all of these include other headers, lots of code: #include "myheader1.h" #include "myheader2.h" #include <string> void foo() { string s("hello world"); // oh no, why does this compile?? } This compiles, so obviously some of the recursively included header files has a using namespace std; somewhere. How would you go about finding out where that offending line of code is? Just using grep on all header files won't really work because that statement is often used inside a function, where it is safe and won't pollute the rest of the code.

    Read the article

  • How does the #! work?

    - by mocybin
    In a script you must include a #! on the first line followed by the path to the program that will execute the script (e.g.: sh, perl). As far as I know though, the # character denotes the start of a comment and that line is supposed to be ignored by the program executing the script. It would seem though, that this first line is at some point read by something in order for the script to be executed by the proper program. Could somebody please shed more light on the workings of the #! ? Edit: I'm really curious about this, so the more in-depth the answer the better.

    Read the article

< Previous Page | 71 72 73 74 75 76 77 78 79 80 81 82  | Next Page >