# www.linuxhelp.netsu


su
visudo
/usr/bin/tail	#shows last 10 lines of fileunrar
type		#shell built in or not
whereis		#shows program info
file		#shows file info (elf...)
ldd		#libraries
tar -xvjf	#tar.bz2
tar -xvzf	#tar.gz


date +%s					#seconds since 01.01.1970
let tage=$(date +%s)/86400; echo $tage;		#days since 01.01.1970
let tage=`date +%s`/86400; echo $tage;		#days since 01.01.1970

/usr/sbin/useradd	#add a user
 -c	#comment
 -u	#user id
 -g	#primary group
 -G	#more groups
 -d	#home directory
 -s	#shell
 -m	#creates homedir

/etc/default/useradd		#defaults
/etc/skel			#homedir template contains: .profile, .Xdefaults, .vimrc
useradd -D [option] <value>	#show/change values

usermod -g <groupe> <username>
chown -R <user> /home/<user>
chgrp -R <group> /home/<user>


mkpasswd		#des hash
mkpasswd --hash=md5	#md5 hash

vipw -s			#edit shadow
hash -r			#kopiert hashtables in speicher

passwd -S		#shows state of current user
passwd -S <username>	#shows state of user
passwd -S -a		#shows state of all users
passwd [-f|-s] <username>		#username
passwd -g <groupname>			#groupname
passwd [-x <max>] [-n <min>]		#
passwd [-w <warn>] [-i <lock>]		#
passwd [-l|-u|-d]			#lock u? delete

/var/log/messages			#logd su -
last					#who has used su - /reboots

find /home -uid 1001
find /home -uid 1001 -print
find /home -depth -uid 1001 -ls


fdisk -l		#list disks/partitions
dd if=/dev/sda bs=512 count=1 | hexdump -C