unix

问题 I have a pipe that all my child processes use, but before a child uses the pipe to talk to the parent I need to clear it so that the parent reads from it correctly. Is there a simple function in C to do this? 回答1: The way to "clear" a pipe is to read from it until the buffer is empty. This doesn't help you. I am guessing that your real problem is that the parent might read data that is mixed from multiple clients. There are two easy solutions to your problem. Always write messages less than

问题 Installed automake using wget http://ftp.gnu.org/gnu/automake/automake-1.15.tar.gz ./configure --prefix=$HOME/local works fine for me. After this step, I ran make and it fails: GEN bin/automake GEN bin/aclocal GEN t/ax/shell-no-trail-bslash GEN t/ax/cc-no-c-o GEN runtest GEN lib/Automake/Config.pm GEN doc/aclocal-1.15.1 GEN doc/automake-1.15.1 help2man: can't get `--help' info from automake-1.15 Try `--no-discard-stderr' if option outputs to stderr make: *** [doc/automake-1.15.1] Error 2 I do

问题 I am new to unix. I want to grep the unmatched pattern from a file1 provided that the patterns are in the file2. The real files are having more than 1000 lines. Example: File1: Hi(Everyone) How(u)people(are)doing? ThanksInadvance File2: Hi(Every ThanksI Required Result: How(u)people(are)doing? I want only the pattern to be used like ("Hi(Every") for the grep.It should return the unmatched line from file1. 回答1: this line works for given example: grep -Fvf file2 file1 The 3 options used above:

问题 I am new to unix. I want to grep the unmatched pattern from a file1 provided that the patterns are in the file2. The real files are having more than 1000 lines. Example: File1: Hi(Everyone) How(u)people(are)doing? ThanksInadvance File2: Hi(Every ThanksI Required Result: How(u)people(are)doing? I want only the pattern to be used like ("Hi(Every") for the grep.It should return the unmatched line from file1. 回答1: this line works for given example: grep -Fvf file2 file1 The 3 options used above:

问题 I am writing a program in C. I have two variables one of which is integer and the other one is float. I want to divide the float by the integer and want to get result in float. I am doing the following: int a; float b=0,c=0; scanf("%d",&a); Here I am doing some computations on b so its value is increased randomly i.e 33 etc. c = b/(float)a; printf("c = %2.f\n", c); The problem is I am getting ' c ' as a rounded number (integer) rather than a float value. How can I get ' c ' as a float value.

问题 I am writing a program in C. I have two variables one of which is integer and the other one is float. I want to divide the float by the integer and want to get result in float. I am doing the following: int a; float b=0,c=0; scanf("%d",&a); Here I am doing some computations on b so its value is increased randomly i.e 33 etc. c = b/(float)a; printf("c = %2.f\n", c); The problem is I am getting ' c ' as a rounded number (integer) rather than a float value. How can I get ' c ' as a float value.

问题 Two commands below : grep ', \\.' enrolments grep ', \.' enrolments got the same result as shown below COMP4001|4368523|Doddau Yobhazravi, . |8684 |M COMP9315|4368523|Doddau Yobhazravi, . |8684 |M COMP9321|4368523|Doddau Yobhazravi, . |8684 |M COMP9331|4368523|Doddau Yobhazravi, . |8684 |M COMP3121|4896558|Vozaila, . |3978/3|F COMP9321|4896558|Vozaila, . |3978/3|F COMP9031|4389601|Yiehil, . |8680/2|M COMP9318|4389601|Yiehil, . |8680/2|M What are the difference between double backslash and

问题 Two commands below : grep ', \\.' enrolments grep ', \.' enrolments got the same result as shown below COMP4001|4368523|Doddau Yobhazravi, . |8684 |M COMP9315|4368523|Doddau Yobhazravi, . |8684 |M COMP9321|4368523|Doddau Yobhazravi, . |8684 |M COMP9331|4368523|Doddau Yobhazravi, . |8684 |M COMP3121|4896558|Vozaila, . |3978/3|F COMP9321|4896558|Vozaila, . |3978/3|F COMP9031|4389601|Yiehil, . |8680/2|M COMP9318|4389601|Yiehil, . |8680/2|M What are the difference between double backslash and

问题 This question already has answers here : How to remove files starting with double hyphen? (7 answers) Closed last month . I have a weird file on a Unix filesystem. It seems to have some special characters in the file name, but I've not been able to remove it. Even if I don't write the name directly in the rm command (and I do ls | rm instead), I get an error that the file doesn't exist. Below some commands that I've tried after a few searches on the internet, in order to debug the issue. Do

问题 This question already has answers here : How to remove files starting with double hyphen? (7 answers) Closed last month . I have a weird file on a Unix filesystem. It seems to have some special characters in the file name, but I've not been able to remove it. Even if I don't write the name directly in the rm command (and I do ls | rm instead), I get an error that the file doesn't exist. Below some commands that I've tried after a few searches on the internet, in order to debug the issue. Do