User:Scott/02

Useful Tech Support Commands

user:scott

Backup Password

• cp /etc/shadow /etc/shadow.bak - (hash of root + user)

Change Password

passwd [username]
passwd –e [username] – (change on startup)

Add / Delete User

adduser [username]
adduser [username] admin
userdel [username]

Updates & Broken Packages

apt-get update
apt-get dist-upgrade

apt-get install --fix-broken
apt-get install ubuntu-desktop

apt-get purge xxx

File System Check

fsidk -l

fsck -fyv /dev/sda1 (f=force y=fix)

shutdown -rF now (reboot, forcing fsck on root filesystem)

Mount & un-Mount

df -h          (show partition booted from)
ls /media      (mounted from GUI)
cat /etc/fstab (partitions and devices = mount on start-up)

mount /dev/sdb1 /mnt/xxx

umount /dev/sdb1 (sudo)

Badblocks

badblocks -nvs /dev/sda1

Backup Home Directory

• date (e.g. 20121223 for Dec 23 2012)

Backup

sudo cp /etc/passwd /etc/shadow /etc/group /home/
dpkg --get-selections > dpkg.out
sudo mv dpkg.out /home/
sudo tar -czf /home/etc.backup.tar.gz /etc/
sudo rsync -avzh /home/ tsbackup@tsbackup:/var/tsbackup/[date-ticketnumber] 2>rsync.log

View error log less rsync.log

Note: on the '''data recovery box''' you will need to add /mnt/sdb1 in front of /home 
      this avoids the need to chroot.

dpkg --get-selections --admindir=/mnt/sdb1/var/lib/dpkg >dpkg.out

Restore

sudo rsync -avzh  tsbackup@tsbackup:/var/tsbackup/[date-ticketnumber]/ /home
sudo dpkg --set-selections < /home/dpkg.out
sudo apt-get -u dselect-upgrade

copy (user passwd) hash from original /etc/shadow

Restore User Permissions

• Create a New User (oem or Bob or Mark) - with Admin. Privileges
  • drwxr-xr-x 23 1001 1001 4096 2011-07-07 13:28 oem

chown –R oem:oem /home/oem (recursively for all sub directories)

File Permissions

chmod 774 dir-name (dir)   rwxrwxr--
chmod 664 filename (files) rw-rw-r--

chmod ugo+rwx /dir/file
chmod ugo-rwx /dir/file

Stress Test

• CPU Temperature

while  true  ; do uptime ; sensors ; sleep 30s; done | tee temp_load.log

stress --cpu 8 --io 4 --vm  2 --vm-bytes 128M  --timeout 4h

• (add --hdd 2 to stress the hard drive as well, though this shouldn't be necessary)