linux:tools: how to edit pdf files

To the Linux Users who need to edit pdf files or figures:
In Linux, you may use pdfedit or xfig etc to edit pdf files, however, they are not good enough. For example, pdfedit is too slow to make users mad ( I am one of victims :-( ). However, you could use an online tool here:

http://www.pdfescape.com

to edit your pdf files. Fast, easy to use...

Linux:shell:command: speed up 'grep'

'grep' is very slow when using it in a UTF-8 mode, specially for a large text file. However, it is fast if using 'C' mode. Use the command 'locale' to check the variable of 'LC_ALL'. Then

export LC_ALL="C"

(from http://tdas.wordpress.com/2008/02/03/speed-up-grep)

I tested it. The "C" mode is faster 50 times than the regular mode!