1. tar
tar -xvlf OpenCV-2.3.1a.tar.bz2
tar -xvzf OpenCV-2.3.1a.tar.gz
tar -cvzf test.tar.gz ./folder/
2. alias
vim ~/.bashrc
alias openpdf='xdg-open'
source ~/.bashrc 或者再開一個標簽頁
3. latex
pdflatex example.tex
openpdf example.pdf