Linux in General

• Find out the number of CPU cores and processors

  See (Jpn)

• Japanese file names are garbled when decompressing compressed zip files on Windows

                   unzip -O Shift-JIS file.zip

• Registration of public key

                  cat id_rsa.pub >> authorized_keys

• Checking the operation of OpenGL

                  glxgears

• Add another name to localhost

  /etc/hosts

                  127.0.0.1	localhost.localdomain	localhost	othername

• Delete files whose names begin with a hyphen

                  rm -- -file.txt

• What i wrote in .ssh/config does not work with Bad owner permissions error.

                  chmod 600 .ssh/config

• When ntpdate fails to set the time, the ntp server is almost always running; just stop the ntp server. On CentOS

                  /etc/init.d/ntp stop
                  chkconfig ntp off

  On Ubuntu

                  service ntp stop
                  aptitude -y install sysv-rc-conf
                  sysv-rc-conf ntp off

• Use python as calculator

                  >>> 1+1
                  2

  Also, to load Math modules that contain various functions

                  >>> from math import *
                  >>> pi
                  >>> 3.14159265359

• Frequently used options in less

  Do not break lines

                  -S

  Display line numbers

                  -N

  Reload

                  -R

• force nfs or samba unmount

                  umount -f hoge

  if that does not work

                  umount -l hoge

• Transfer only files with specific extentions via rsync

                  rsync -auvz --include='*/' --include='*.hoge' --exclude='*' sourceplace sendplace

• Do not transfer only files with certain extensions in rsync

                  rsync -auvz --include='*/' --exclude='*' sourceplace sendplace

• I want to sort by file type in ls

  In bashrc

                  alias ls='ls -X --color=always'

  if you always do.