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LPI 101 tips

August 8th, 2012 Leave a comment Go to comments

I just passed the LPI-101 exam and scored 700 of 800.
Here are some study tips:

vi ? searches in reverse order
GRUB_TIMEOUT paramete The value of this parameter is in sec
unset is used to remove a env variable
ldd `which cat` can be used to find library dependecy. ldd prints library required by a cmd
LD_LIBRARY_PATH is an env that should be used for shared library
/etc/ld.so.cache is where ld.so finds library quickly
APM is an older version of ACPI
/proc/interrupts contains information about IRQ address
LILO does not use /boot only GRUB
How to read “kernel ring buffer”? Answer: dmesg
In vi editor how to go to a new line and insert: Answer: o
Function of sticky bit? (means that only the file owner and the superuser may remove or rename files from that directory.) usually set on /tmp;
Changes grub legacy to grub2: Answer: Grub 2 counts at: 0:1 – grub legacy 0:0
grep -f or fgrep: searches files for one or more pattern arguments. It does not use regular expressions; instead, it does direct string comparison
rpm -qv – search for a package
rpm -qi – show info of a package
rpm -ql – show all files owned by a package
rpm -qf – shows owning packages from a file
rpm -F – freshen , will upgrade if a package exists
rpm -qp –changelog – will list history of installed rpm
rpm -qc – list where config files are at
rpm -U – will upgrade the rpm package
sed -i – is to make change in-place example: sed -i ‘s/foo/foobar/g’ file.txt
SCSI-I supports only 8 devices including the adapter, so 7 disks max.
df -i prints the Inodes of all volumes
echo $! shows the id of the last process on bg
quotaon is the last cmd to run during boot when quota is enabled
repquota show disk quota details
grpquota on /etc/fstab enables group quota
quota foobar will list quota info of a user
renice highest priority is -20 and lowest is 19, default is 0
nice default is to set to 10
default kill SIGTERM is 15, kill 123 is same of: kill -15 123 and kill -s SIGTERM 123
to allow anyone to mount should have option ‘user’ on /etc/fstab
expand converts tab to spaces
to run quite cmd >/dev/null 2>&1
cmd1 ; cmd2 will run even if the cmd1 fail, cmd1 && cmd2 runs only if cmd1 was OK
tune2fs is used to change parameters in the superblock, like how often chkdisk run on a EXT2 volume
mke2fs -j creates a ext3 with journaling
lsattr list ext3 attributes of a file
mkdir -p creates parents dir as needed ex: mkdir -p /tmp/foo/bar/yoyo
USB 2.0 needs kernel at least 2.4
whereis locate the binary,source and man pages for a cmd
alien converts rpm to deb packages
mke2fs -T
cat -n and nl list numbers on each line (nl will not list empty lines)
makefile usually contains: clean, install, uninstall
to change CR-LF: tr “rn” to change to LF tr -d “r” CR = r LinuxFeed(newline) = n
killall -s SIGUSR1 apache2 or killall -10 apache2 – will send SIGUSR1 to all process running w/ apache2 user
Crtl-C equal SIGINT
alsactl set the ALSA sound system
when reading man pages command ‘col’ removes extra characters
setfacl Granting an additional user read access: ‘setfacl -m u:lisa:r file’
‘set -o vi’ on .bashrc will recognize vi keystrokes after login
‘Hard Disk Error’ Stage 1 on the GRUB boot process, it means unable to determine size and geometry of the disk
telinit 1, changes to runlevel 1 (stopping services) and allowing maintence to be made.
dpkg -L package.deb lista all files in that package
the USB device filesystem is under /proc/bus/usb
/etc/mtab lists mounted disks
vi to cp lines do 17yy
rpm2cpio will convert rpm to cpio
quotaon enables disk quota on a filesystem
after changing lilo conf files should run cmd ‘lilo’ grb-update does the same when editing grub conf files.
umask 077 (0, owner rwx) (7, Group no permissions) (7, Other no permissions)
dpkg-reconfigure will ask all instalation questions as being installed for first time
lspci , can list many things but not the MAC address
/etc/yum.repos.d is where addiotion repository should be placed
chmod 2000 will set SGID permission on
!! will repeat last comand exceuted in the shell
shutdown -c – will cancel a running shutdown process
tun2fs can transform a ext2 journal to ext3 journal
installing custom grub – /custom-grub/boot/grub
rpm -K, rpm –checksig, rpm -V – all checks the signature
tac prints files content in reverse order

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