file-descriptor

What I am going to do is to create multiple output steams in a python function, and refer them as 1 , 2 , 3 .....: In test.py : def main(): ... print >>fd1, 'words1' print >>fd2, 'words2' print >>fd3, 'words3' ... Redirect it while using: python test.py 1>1.txt 2>2.txt 3>3.txt The content of these files: 1.txt -> words1 2.txt -> words2 3.txt -> words3 The question is, how to create those fd1 , fd2 , fd3 ? Added: I have used this: outfiles = {} for _ in range(3): fd = os.dup(1) outfiles[fd] = os.fdopen(fd, 'w') def main(): for no in outfiles: print >>outfiles[no], "foo" print >>outfiles[no],

I did the commands ( source ): $ exec 3>/tmp/thirdfile $ exec 4>/tmp/fourthfile $ echo drib >&3 $ echo drab >&4 $ echo another drib >&3 $ echo another drab >&4 $ exec 3>&- $ exec 4>&- How can I see the file handles, something like with lsof -l ? I don't understand, why not just use lsof: lsof -p $$ $$ being a shell variable that holds the shell's process ID You can also limit to just file descriptors like: lsof -a -d0-65535 -p $$ On Linux, you can do something like ls -l /proc/$$/fd , which will show you what file descriptors are open in your shell. Of course, substitute $$ with other numbers

I want to run programs in linux by a button click an therefore I wrote a function execute : void execute(const char* program_call, const char* param ) { pid_t child = vfork(); if(child == 0) // child process { int child_pid = getpid(); char *args[2]; // arguments for exec args[0] = (char*)program_call; // first argument is program_call args[1] = (char*)param; // close all opened file descriptors: const char* prefix = "/proc/"; const char* suffix = "/fd/"; char child_proc_dir[16]; sprintf(child_proc_dir,"%s%d%s",prefix,child_pid, suffix); DIR *dir; struct dirent *ent; if ((dir = opendir (child

If I open the same file twice, will it give an error, or will it create two different file descriptors? For example a = open("teste.txt", O_RDONLY); b = open("teste.txt", O_RDONLY); In this case, since you're opening both files as read-only, you will get two different file descriptors that refer to the same file. See the man page for open for more details. To complement what @Drew McGowen has said, In fact, in this case, when you call open() twice on the same file, you get two different file descriptors pointing to the same file (same physical file). BUT , the two file descriptors are

When I try to refer to two process substitution pipes in a bash function, only the first one referenced works. The second one gives a "bad file descriptor" error like so: $ foo(){ > cat "$1" > cat "$2" > } $ foo <(echo hi) <(echo bye) hi cat: /dev/fd/62: Bad file descriptor $ It appears that the second pipe is dropped once one is referenced, but a) I cannot seem to confirm this behavior in any documentation and b) I wish it wouldn't. =) Any ideas on what I'm doing wrong? FWIW I'm doing this to make a wrapper to use Mac OS X's FileMerge graphical diff tool instead of the command line one, which