When somebody asks me about how strong you are in unix/linux internals ? What do they really mean ? Though i have some idea, i would like to hear from some experts that, what is really meant by unix/linux internals. My ideas are, i have to be strong in, linux boot process user creation how does a command executes filesystem related ...
Whenever i write grep -v "0" in order to ignore the 0 number somehow the number 10 is getting ignored as well. Please help me use the grep -v "0" with ignoring 0 in the process and not ignoring 10 ...
I am seeing if there is a way for getopts to handle switches with strings instead of characters. For example, I would like to supply something like this: script.ksh -file1 file1.txt -file2.txt Instead of: script.ksh -f file1.txt -g file2.txt Is this possible with unix getopts? Thanks! ...
Hi, Is there anyway to set environment variables in linux using C? I tried setenv() and putenv(), but they don't seem to be working for me. Thanks in advance. ...
What are some specific[1] real-world code[2]/design examples, personal anecdotes, mistakes learned (with more emphasis on personal anecdotes, mistakes learned instead of pointing out third-party software) that best illustrate the programming philosophy of Unix? For a start, here's Raymond's summarization of the philosophy from The Art of...
Is there any way to obtain Unix Time with nanoseconds with strftime in bash? My line for unix time : <command> | awk '{ print strftime("%s"), $0; }' I cannot use date +%N because date is only evaluated once. Is there any work around? ...
Sometimes when I edit my file using vi or vim, my file just freezes. Even if I type Ctrl+C or Ctrl+D, it still freezes there. I kill -9 <pid> from another terminal, the pid is killed, but the file still freezes there. I guess I must have typed some combination of key which I do not know. Does anybody have an idea? ...
I have a data that looks like this: AB208804_1 446 576 AB208804_1orf 0 AB208804_20 446 576 AB208804_20orf 0 I want to convert them into this: AB208804 446 576 AB208804orf 0 AB208804 446 576 AB208804orf 0 just by removing _\digit part in column 1 and 4. Why this line doesn't work: sed 's/_\d+//g' What's the correct way to do it...
I have encountered a problem where even after my server side close()-ed the socket, the client side still can do a single write(), only the second write() will return SIGPIPE, this causes me to loose data as I do not have application level handshake and solely relying on the return value of write(). Is there a way for me to get SIGPIPE s...
In linux, if I put a command in a script that contains an alias, I see that it doesn't get expanded. How can I fix that? I am using bash. ...
My understanding was that one could not control the file descriptor (integer) assigned by the OS when opening a new file using open(). How then is it possible in a bash shell to assign a specific file descriptor using a command like exec 5>&1 (I suppose I could find out by reading the bash sources...) ...
For a website I'm working on I want to be able to automatically update the "This page was last modified:" section in the footer as I'm doing my nightly git commit. Essentially I plan on writing a shell script to run at midnight each night which will do all of my general server maintenance. Most of these tasks I already know how to automa...
Can a process 'foo' write to file descriptor 3, for example, in such a way that inside a bash shell one can do foo 1>f1 2>f2 3>f3 and if so how would you write it (in C)? ...
I am writing a C UNIX program that is threaded and shares one variable across all threads. What would be the easiest way to acquire a lock on this variable? I can't find any small libraries just for locking in UNIX. Any suggestions how to do this? Thanks, Boda Cydo. ...
Example: I have a file: FILENAME.EXT and would like to extract FILENAME without the .EXT I want to be able to use the extensionless filename for a command which only accepts filenames without its extensions. I have a utility called BCHECK which accepts as its argument a filename with no extensions. Using BCHECK *. does not work because a...
Hello guys, Can some one please tell me an approach for finding security flaws in a given code. For ex: in a given socket program. Any good examples or good book recommendations are welcome. Thanks & Regards, Mousey ...
I have a VPS in cloud environment based on XEN Virtualization platform. /etc/fstab looks like that: LABEL=PRGMRDISK1 / ext3 errors=remount-ro 0 0 As far as I know IO can pretty easily become a bottleneck if some other VPS neighbor will use it intensively(IO bandwidth is a shared resource for multiple guest VPS). ...
I want to send the fax to the user using hylafax sendfax command. But the user will type only fax number. But I need to add three digit number infront of the fax number. How to add the three digits in front of the fax number. ...
I am reading GNU/Linux application programming the 2nd edition,you can reach what am reading from here.After I write the code similar to his,but it work strangely: $ ./shell ./shell>>quit $ ./shell ./shell>>date Sun Aug 8 21:19:37 CST 2010 ./shell>>quit $ ./shell ./shell>>abc execlp failed: No such file or directory ./shell>>quit ./she...
Question: I need to make some system calls in my C# applications. Unfortunately, this behaves differently on Linux than on UNIX. Now I used to switch the Operating system at runtime like this If Environment.OSVersion.Platform = System.PlatformID.Unix Then ' Linux/Unix ' ElseIf Environment.OSVersion.Platform = System.PlatformID.Mac...