Ubuntu/Linux Hacks

1、PDF 文件乱码 : 

sudo apt-get install xpdf-chinese-simplified xpdf-chinese-traditional poppler-data

2、如何设置动态域名: 

w3m -no-cookie -dump ''

3、清理内存

Writing to this will cause the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free.

To free pagecache:

echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:

echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes:

echo 3 > /proc/sys/vm/drop_caches
As this is a non-destructive operation, and dirty objects are not freeable, the user should run "sync" first in order to make sure all cached objects are freed.

This tunable was added in 2.6.16.