13 01:28 637 dr-xr-xr-x 3 rpcuser rpcuser 0 Feb 13 01:28 666These directories are called process directories, as they are named after a program's processID and contain information specific to that process. The owner and group of each processdirectory is set to the user running the process. When the process is terminated, its /proc/process directory vanishes.Each process directory contains the following files:• cmdline — Contains the command issued when starting the process.• cwd — A symbolic link to the current working directory for the process.• environ — A list of the environment variables for the process. The environment variable isgiven in all upper-case characters, and the value is in lower-case characters.• exe — A symbolic link to the executable of this process.• fd — A directory containing all of the file descriptors for a particular process. These are givenin numbered links:total 0 lrwx------ 1 root root 64 May 8 11:31 0 -> /dev/null lrwx------ 1root root 64 May 8 11:31 1 -> /dev/null lrwx------ 1 root root 64 May 811:31 2 -> /dev/null lrwx------ 1 root root 64 May 8 11:31 3 -> /dev/ptmxlrwx------ 1 root root 64 May 8 11:31 4 -> socket:[7774817] lrwx------ 1root root 64 May 8 11:31 5 -> /dev/ptmx lrwx------ 1 root root 64 May 811:31 6 -> socket:[7774829] lrwx------ 1 root root 64 May 8 11:31 7 ->/dev/ptmx• maps — A list of memory maps to the various executables and library files associated with thisprocess. This file can be rather long, depending upon the complexity of the process, butsample output from the sshd process begins like the following:08048000-08086000 r-xp 00000000 03:03 391479 /usr/sbin/sshd08086000-08088000 rw-p 0003e000 03:03 391479 /usr/sbin/sshd08088000-08095000 rwxp 00000000 00:00 0 40000000-40013000 r-xp 0000000003:03 293205 /lib/ld-2.2.5.so 40013000-40014000 rw-p 00013000 03:03 293205/lib/ld-2.2.5.so 40031000-40038000 r-xp 00000000 03:03 293282/lib/libpam.so.0.75 40038000-40039000 rw-p 00006000 03:03 293282/lib/libpam.so.0.75 40039000-4003a000 rw-p 00000000 00:00 04003a000-4003c000 r-xp 00000000 03:03 293218 /lib/libdl-2.2.5.so4003c000-4003d000 rw-p 00001000 03:03 293218 /lib/libdl-2.2.5.so• mem — The memory held by the process. This file cannot be read by the user.• root — A link to the root directory of the process.Chapter 5. The proc File System66
