.\"
.\" Copyright 2007 Trent Waddington <trent.waddington@gmail.com>
.\"
.\" This program is free software; you can redistribute it and/or modify
.\" it under the terms of the GNU General Public License as published by
.\" the Free Software Foundation; either version 2 of the License, or
.\" (at your option) any later version.
.\"
.TH PEEKFD 1 "2021-12-01" "psmisc" "User Commands"
.SH NAME
peekfd \- peek at file descriptors of running processes
.SH SYNOPSIS
.B peekfd 
.RB [ \-8 , \-\-eight\-bit\-clean ]
.RB [ \-n , \-\-no\-headers ]
.RB [ \-c , \-\-follow ]
.RB [ \-d , \-\-duplicates\-removed ]
.RB [ \-V , \-\-version ]
.RB [ \-h , \-\-help ]
.I pid
.RI [ fd ]
.RI [ fd "] ..."
.SH DESCRIPTION
.B 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.
.SH OPTIONS
.IP -8
Do no post-processing on the bytes being read or written.
.IP -n
Do not display headers indicating the source of the bytes dumped.
.IP -c
Also dump the requested file descriptor activity in any new child
processes that are created.
.IP -d
Remove duplicate read/writes from the output.  If you're looking at a
tty with echo, you might want this.
.IP -v
Display a version string.
.IP -h
Display a help message.
.SH FILES
.BI /proc/ * /fd
.RS
Not used but useful for the user to look at to get good file descriptor
numbers.
.SH ENVIRONMENT
None.
.SH DIAGNOSTICS
The following diagnostics may be issued on stderr:
.TP
.BI "Error attaching to pid " <PID>
An unknown error occurred while attempted to attach to a process, you
may need to be root.
.SH BUGS
Probably lots.  Don't be surprised if the process you are monitoring
dies.
.SH AUTHOR
.MT trent.waddington@gmail.com
Trent Waddington
.ME
.SH "SEE ALSO"
.BR ttysnoop (8)