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Full Discussion: file descriptors
Top Forums UNIX for Dummies Questions & Answers file descriptors Post 46830 by a25khan on Tuesday 27th of January 2004 05:01:21 PM
Old 01-27-2004
user oombera,

thanks for your answer,
yeah i see where are we heading from here. when i read it in my text, didn't make any sense. but when you said that "unix reads the files by using their respective numbers(file descriptors)" then i really understood the idea behind this. i have one more question though, what does this have to do with processes!?
a25khan
 

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PEEKFD(1)							   User Commands							 PEEKFD(1)

NAME
peekfd - peek at file descriptors of running processes SYNOPSIS
peekfd [-8,--eight-bit-clean] [-n,--no-headers] [-f,--follow] [-d,--duplicates-removed] [-V,--version] [-h,--help] pid [fd] [fd] ... DESCRIPTION
peekfd attaches to a running process and intercepts all reads and writes to file descriptors. You can specify the desired file descriptor numbers or dump all of them. OPTIONS
-8 Do no post-processing on the bytes being read or written. -n Do not display headers indicating the source of the bytes dumped. -c Also dump the requested file descriptor activity in any new child processes that are created. -d Remove duplicate read/writes from the output. If you're looking at a tty with echo, you might want this. -v Display a version string. -h Display a help message. FILES
/proc/*/fd Not used but useful for the user to look at to get good file descriptor numbers. ENVIRONMENT
None. DIAGNOSTICS
The following diagnostics may be issued on stderr: Error attaching to pid ... An unknown error occured while attempted to attach to a process.. you may need to be root. BUGS
Probably lots. Don't be surprised if the process you are monitoring dies. AUTHOR
Trent Waddington <trent.waddington@gmail.com> SEE ALSO
ttysnoop(8) Linux APRIL 2007 PEEKFD(1)
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