"With you...I imagine a lifetime of smiling every time i see you."

assume you must be root to edit anything in /etc

managing services in /etc/init.d
./servicename start, restart, stop, status
common service names:

email aliases for sendmail

/etc/cron.allow and cron.deny
specifies which users are or aren't able to create cron jobs

cron configuration

numbers = minute, hour, day, month, day of week
days of week = 0 (sunday) thru 6 (saturday)
multiple entries in a single slot can be seperated by commas
example: 0,10,20,30,40,50 * * * * <--- runs every 10 minutes


# run-parts
01 * * * * root nice -n 19 run-parts --report /etc/cron.hourly   <---runs one minute past every hour
02 4 * * * root nice -n 19 run-parts --report /etc/cron.daily    <---runs at 4:02am
22 4 * * 0 root nice -n 19 run-parts --report /etc/cron.weekly  <---runs at 4:22am every sunday
42 4 1 * * root nice -n 19 run-parts --report /etc/cron.monthly <---runs at 4:42am every 1st of the month

contains CUPS configuration files

user creation defaults for useradd

DHCP server settings

NFS shares configuration

devices that are automatically mounted during boot
/dev/hda6 / ext3 noatime 1 1
/dev/hda1 /boot ext3 noatime 1 2
/dev/hda9 /home ext3 noatime 1 2
/dev/hdc /mnt/cdrom auto umask=0,users,iocharset=utf8,noauto,ro,exec 0 0
none /proc proc defaults 0 0
/dev/hda7 /tmp ext3 noatime 1 2
/dev/hda10 /usr ext3 noatime 1 2
/dev/hda8 /var ext3 noatime 1 2
/dev/hda5 swap swap defaults 0 0

device, mount dir, fstype, mount options, dump backup frequency, fsck priority

mount options:
ro = read-only
rw = read-write
user = non-root user can mount the filesystem
noauto = don't automount filesystem
exec/noexec = allow execution of files or don't
suid/nosuid = allow SUID/SGID access or don't
noatime = access times are not updated upon reads

dump backup frequency
0 = don't backup this filesystem

fsck priority:
0 = never check, 1 = reserved for root partition, checked first, 2 = check other partitions second

wu-ftpd configuration

group information

shadowed passwords for groups, only viewable by root

hostname of system

static hostname resolution

ACL for inetd/xinetd

ACL for inetd/xinetd

apache configuration. location varies.../etc/httpd or /etc/apache2, etc

super server settings, deprecated...replaced by xinetd.conf

daemons can be stopped, started, restarted, etc from this directory
./service <action>

/etc/inittab (Ubuntu replaces the init process with upstart, closest comparable file is /etc/init/rc-sysinit.conf)
init config file
some contents...
# Default runlevel. The runlevels used by Mandrakelinux are:
#   0 - halt (Do NOT set initdefault to this)
#   1 - Single user moden

#   2 - Multiuser, without NFS (The same as 3, if you do not have networking)
#   3 - Full multiuser mode
#   4 - unused
#   5 - X11
#   6 - reboot (Do NOT set initdefault to this)

# Run gettys in standard runlevels
1:2345:respawn:/sbin/mingetty tty1 <---- creating intial virtual terminals
2:2345:respawn:/sbin/mingetty tty2

pre-login banner message
usually contains system information such as distribution version

index of system library names and locations (binary file)

system library paths to be included in the index

lilo settings

contains default user creation settings such as password aging, UID/GID ranges, etc.

listing of man page paths (and other man configuration). most man pages are located in /usr/share/man by default

kernel module configuration

message of the day (motd)
it is displayed each time a user logs into the system

lists currently mounted filesystems

bind DNS server settings

configuration of network interfaces

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet static

presence of file prevents all non-root users from logging in. file must be removed to lift restriction

NTP configuration
public servers can be found at:
current time at:

/etc/passwd entries are setup like so:
username:password (x if shadowed, * if account disabled):userid#:primarygroupid#:fullname:homedir:shell
finger information is retrieved from here
shell value of "/bin/false" gives an account no login shell

printer settings. first printer listed is considered the default printer unless PRINTER environment variable is set.
lp = print device used by printer
sd = spool directory used by printer
rm = remote hostname of printer
rp = remote printer's name
if = filter location
mx = max size of a print job, 0 = no limit
lf = location of error log for printer

/etc/rc.d/ .... rc3.d rc4.d, etc
runlevels defined..K(kill process), S(start process)

DNS client configuration
sample contents:
nameserver ... (secondary server..etc)

samba configuration. see samba page for details

sendmail configuration

network services and their ports

user password information only viewable by root account

listing of available shells on the system

system defaults for the following files...
.bash_profile - environment variables
.bashrc - commands that run at each new shell login
.bash_logout - commands ran at logout

openSSH server configuration
note: never allow root access over ssh
and it's best to lock down ssh access to only those users that require it (AllowUsers username1 username2)

/etc/syslog.conf (/etc/rsyslog.d/50-default.conf in ubuntu)
syslog configuration

X11 configs see my X windows page for more details

super server settings