FHS Flashcards
/boot
The OS Kernal - contains the actual operating system, and other files required by the boot loader (LILO or GRUB)
vmlinuz
The linux kernal, located in /boot
contains the actual operating system, and other files required by the boot loader (LILO or GRUB)
/bin
/bin
General Utilities - most important executable programs (mostly system programs) which are nescessary for the file system to boot. Includes mount and mkdir. Also contains programs that are nescessary to get a damaged system running again if only the file system containing the root directory is available.
Where is mkdir, the system program, located?
/bin
Difference between /bin and /usr/bin
/bin has files required on boot and system repair, /usr/bin has additional programs not required in that respect.
/sbin
“special system programs” - Like /bin, /sbin contains programs that are nec- essary to boot or repair the system. However, for the most part these are system configuration tools that can really be used only by root. “Normal” users can use some of these programs to query the system, but can’t change anything. As with /bin, there is a directory called /usr/sbin containing more system programs.
programs that are nescessary to boot or repari the system, but for the most part are only really used by root
/sbin
/lib
System Libraries - This is where the “shared libraries” used by programs in /bin and /sbin reside, as files and (symbolic) links. Shared libraries are pieces of code that are used by various programs. Such libraries save a lot of resources, since many processes use the same basic parts, and these basic parts must then be loaded into memory only once; in addition, it is easier to fix bugs in such libraries when they are in the system just once and all programs fetch the code in question from one central file.
/dev
Device Files - forms the interface betwenn the shell and to the device drivers inside the kernel.
what is a character device
Device that processes single characters. eg. mouse, keyboard, terminal
what is a block device
device that processes characters in block (eg of 512 bytes), such as hard disks, zip disks, etc
how are device files outputted in ls -l?
as b or c for block or character device.
where can you discard output that you will never need?
/dev/null
/dev/null
a ‘dust bin’ for discarding output
/etc
config files - v important! - contains configuation for most programs.
/etc/fstab
describes all mountable file systems and their properties
/etc/hosts
one of the configs for TCP/IP network. Maps the names fo network hosts to their IP addresses.
/etc/inittab
config for init program and thus for the system start
/etc/init.d/*
dir for the “init scripts” for various system services. Used for startup/shutdown when the system is booted or switched off.
> red hat uses /etc/rc.d/init.d
/etc/issue
contains the greeting that is output before a user is asked to log in. Frequently contains the name of the vendor that installed.
/etc/motd
contains “message of the day” that appears after a use has successfully logged in.
/etc/mtab
lists all mounted file systems and mount points.
/etc/passwd
list of all users that ore known to the system, with various user-specific info.
/etc/shadow
encrypted passwords for users, not readable by normal users.
describes all mountable file systems and their properties
/etc/fstab
config files for the TCP/IP network
/etc/hosts
config files for the init program for system start
etc/inittab
contians init scripts for various system services.
/etc/init.d/*
/etc/rc.d/init.d (red hat)
contains greeting when prompted to login
/etc/issue
contains message that appears after successful login
/etc/motd
list of all currently mounted file systems
/etc/mtab
list of users and user-specific info
/etc/passwd
contains user passwords
/etc/shadow
/opt
intended for 3rd party softwar.. Complete packages that are installable without conflicting with distribution files or locally installed files
/usr
various subdirectiroise with programs and data files not esential for booting or reparing the system
/usr/bin
system programs not essential to boot or sys repair
/usr/lib
further libraries (not for /bin or /sbin)
/usr/local
dir for files used by the lolcal sysadmin. Nothing should be put here by the distribution.
/usr/share
architecture-independend data.
/usr/share/doc
documentatin and howtos
/usr/share/info
info pags
/usr/share/man
manual pages
/usr/src
source code for kernal and other programs
/proc
a pseudo fs, dynamically create by kernal when needed. contains info about system runtime, such as running processes and PID
/proc/cpuinfo
info about cup and clock frequency
/proc/devices
devices supported by the kernal.
/proc/dma
list of dma channels in use. (not interesting or important lol)
/proc/interrupts
list of hardware interrupts
/proc/ioports
list of i/o ports
/proc/kcore
it makes available the computer’s complete RAM and is required for debugging the kernel. Requires root for reading. Stay away!
/proc/loadavg
contains three nmubres measuring cpu for the last 1, 5, 15 minutes
/proc/meminfo
Displays memory and swap usage, used by the free porgram
/proc/scsi
all scsi devices
/proc/verison
version nmber and compliation date of the current kernel.
/sys
pseudo dir. “hardware control” shows a lot about available hardware
/var
Dynamically changing files, distribute across diff directiorise. Data create from executing other programs is stored here.
/var
Dynamically changing files, distribute across diff directiorise. Data create from executing other programs is stored here.
what program is system log files handled by
the syslog service
How do you access the kernel messages before syslogd start?
via ‘dmesg’
/tmp
transient files, for temporayr files.
/media
generated automatiaclly that can serve as mount points for cdroms and floppies. Further mountpoints can be made here.
/mnt
Other storage media. Mount point for short-term mounting of additiional storage medie
/home
User home directories
/root
administrators home dir
