Finally, finally, congratulations ~ Rankings
Jan 26, 2011
Angry Terminal
Last night I got the idea that using different colors in shell prompt to tell the user about the result of last command executed, e.g. red for failed execution and green for success.
It's really easy to do that in the ultimate shell, all I need is a function and a prompt using it:
Then I realized I can go one step further to help terminal express her feeling, I always feel she is angry with me.
So I changed the function a bit, like this:
Now Miss Terminal can tell me what she thinks when I do something wrong!
It's really easy to do that in the ultimate shell, all I need is a function and a prompt using it:
function prompt_base_color() {
if [[ $? == "0" ]]; then
echo $PR_GREEN
else
echo "$PR_RED"
fi
}
PROMPT='$PR_SET_CHARSET$PR_STITLE${(e)PR_TITLEBAR}$(prompt_base_color)%D{%H:%M} $PR_GREEN%~ $PR_RED$(git_prompt_info)$PR_NO_COLOUR'
Then I realized I can go one step further to help terminal express her feeling, I always feel she is angry with me.
So I changed the function a bit, like this:
function prompt_base_color() {
if [[ $? == "0" ]]; then
echo $PR_GREEN
else
txt=`cat ~/.zsh/my_ass.txt`
echo "$txt\n$PR_RED"
fi
}
Now Miss Terminal can tell me what she thinks when I do something wrong!
Nov 26, 2010
QorCMS preview
Qor is the admin tool we build for rails. It's not public released yet but already used by some of our clients. It's like the Django one but only better!
Qor Enterprise CMS Demo from Felix Sun on Vimeo.
Nov 4, 2010
Compiling Google mod_pagespeed on Archlinux
Google released its awesome apache module mod_pagespeed recently. Unfortunately only .deb/.rpm packages are provided officially. For arch user, we have to compile it by ourselves.
Based on google's howto, we need depot_tools to compile mod_pagespeed. There is an aur package depot_tools-svn, but seems not work now because arch switched to python 3.
So I downloaded depot_tools myself and put it in my ~/scripts/depot_tools.
To make depot_tools work, you need to switch to python2:
Next step we download mod_pagespeed source code use depot_tools:
You're ready to compile now.
I got an error when I compile it on my box:
After digging a while, I made this patch to fix the error:
ps: I also deployed mod_pagespeed to our centos staging server, the whole process is very smooth. The result is also very impressive: gzip, cache-control, inline assets, etc. etc. all suddenly work like a charm. The only problem is with extend_cache filter: it modified asset name correctly, but when brower send request to those assets, the server reponds with 404 error. I have to disable rewrite_javascript and extend_cache filter to make our sites work correctly:
Based on google's howto, we need depot_tools to compile mod_pagespeed. There is an aur package depot_tools-svn, but seems not work now because arch switched to python 3.
So I downloaded depot_tools myself and put it in my ~/scripts/depot_tools.
mkdir -p ~/scripts
cd ~/scripts
svn co http://src.chromium.org/svn/trunk/tools/depot_tools
To make depot_tools work, you need to switch to python2:
sudo rm /usr/bin/python
sudo ln -s /usr/bin/python2 /usr/bin/python
sudo rm /usr/bin/python-config
sudo ln -s /usr/bin/python2-config /usr/bin/python-config
Next step we download mod_pagespeed source code use depot_tools:
mkdir ~/mod_pagespeed # any directory is fine
cd ~/mod_pagespeed
gclient config http://modpagespeed.googlecode.com/svn/trunk/src
gclient sync --force # this will download all source code
You're ready to compile now.
cd ~/mod_pagespeed/src
make BUILDTYPE=Release # BUILDTYPE defaults to 'Debug'
I got an error when I compile it on my box:
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.5.1/../../../../include/c++/4.5.1/utility:71:0,
from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.5.1/../../../../include/c++/4.5.1/algorithm:61,
from ./net/instaweb/util/fetcher_test.h:24,
from ./net/instaweb/util/cache_fetcher_test.h:27,
from net/instaweb/util/cache_fetcher_test.cc:19:
...
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.5.1/../../../../include/c++/4.5.1/bits/stl_map.h:87:5: instantiated from here
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.5.1/../../../../include/c++/4.5.1/bits/stl_pair.h:77:11: error: ?std::pair<_t1,>::second? has incomplete type
./net/instaweb/util/public/cache_interface.h:28:7: error: forward declaration of ?struct net_instaweb::SharedString?
After digging a while, I made this patch to fix the error:
Index: net/instaweb/util/public/cache_interface.h
===================================================================
--- net/instaweb/util/public/cache_interface.h (revision 137)
+++ net/instaweb/util/public/cache_interface.h (working copy)
@@ -21,6 +21,7 @@
#include <string>
#include "net/instaweb/util/public/string_util.h"
+#include "net/instaweb/util/public/shared_string.h"
namespace net_instaweb {
ps: I also deployed mod_pagespeed to our centos staging server, the whole process is very smooth. The result is also very impressive: gzip, cache-control, inline assets, etc. etc. all suddenly work like a charm. The only problem is with extend_cache filter: it modified asset name correctly, but when brower send request to those assets, the server reponds with 404 error. I have to disable rewrite_javascript and extend_cache filter to make our sites work correctly:
ModPagespeedDisableFilters rewrite_javascript
ModPagespeedDisableFilters extend_cache
Oct 26, 2010
On Vim again
There's only 10 kinds of people, those who use Vim, and those who use Emacs.
Two months ago I don't know whether I'm wrong on choosing Vim as my editor, now I know I made a right decision, one of those few right decisions in my life.
Emacs can do everything, except editing texts, everyone knows it. But I didn't expect that I can't simply *copy a line* before I learned to use it. I can copy a line by press y twice in Vim by one finger while the other hand is filling my mouth with cookies; I need to move the cursor to the beginning of a line, press C-S-e, then press M-w to copy the damn line.
Of course I can write a macro and map the copy-line macro to my favorite keys. Yes, I can also write a text editor myself. Those two doesn't have much differences, no?
Be serious: I really wrote a macro to do that, the problem is when I tried to map it to some key I failed - there's no reasonable key combination left for me to use. C-y? that's for yank, C-c? that's a common prefix, etc. etc. I don't want to match copy-line to something like C-c C-t C-y, that just won't save my time and stupid.
Luckily Emacs do leave some key combination possibilities for me, so I can quick access find file/buffer functions. I'd say ido is really awesome, that's what I miss when I switch back to Vim. Vim lacks a decent file navigator. FuzzyFinder is cool, but it's turtle slow on large project.
I also miss ruby-test-mode, which can do exactly the same thing but faster than my little rubytest.vim.
Emacs follows totally different philosophy than Vim: Emacs included everything in itself, while Vim leave everything but editing to others. An example is Tramp. Tramp is really cool because you can prefix the file name with 'su::/' or 'su:root@hostfoo' when you want to edit a file you have no privileges or on a remote server, it's not convenient to do the same thing in Vim. But I found myself more like to open a terminal and sudo vim /etc/hosts. (btw. emacs in console sucks.) I believe Emacs fits certain people, people who like to do everything in one place.
Sometimes I think Emacs is for people who're using poor window manager. Because if you're using something like Gnom's default metacity, it's hard to create a new console, do something there while reading stuff in your text editor, then switch back to your editor. In short, most window managers doesn't allow you to manipulate layout between your editor and task windows easily. But if you're using tiling window manager like XMonad, I think Vim is the best fit because you can always do something in a new window easily while looking at your editor.
Emacs is cool. I just like Vim more.
Two months ago I don't know whether I'm wrong on choosing Vim as my editor, now I know I made a right decision, one of those few right decisions in my life.
Emacs can do everything, except editing texts, everyone knows it. But I didn't expect that I can't simply *copy a line* before I learned to use it. I can copy a line by press y twice in Vim by one finger while the other hand is filling my mouth with cookies; I need to move the cursor to the beginning of a line, press C-S-e, then press M-w to copy the damn line.
Of course I can write a macro and map the copy-line macro to my favorite keys. Yes, I can also write a text editor myself. Those two doesn't have much differences, no?
Be serious: I really wrote a macro to do that, the problem is when I tried to map it to some key I failed - there's no reasonable key combination left for me to use. C-y? that's for yank, C-c? that's a common prefix, etc. etc. I don't want to match copy-line to something like C-c C-t C-y, that just won't save my time and stupid.
Luckily Emacs do leave some key combination possibilities for me, so I can quick access find file/buffer functions. I'd say ido is really awesome, that's what I miss when I switch back to Vim. Vim lacks a decent file navigator. FuzzyFinder is cool, but it's turtle slow on large project.
I also miss ruby-test-mode, which can do exactly the same thing but faster than my little rubytest.vim.
Emacs follows totally different philosophy than Vim: Emacs included everything in itself, while Vim leave everything but editing to others. An example is Tramp. Tramp is really cool because you can prefix the file name with 'su::/' or 'su:root@hostfoo' when you want to edit a file you have no privileges or on a remote server, it's not convenient to do the same thing in Vim. But I found myself more like to open a terminal and sudo vim /etc/hosts. (btw. emacs in console sucks.) I believe Emacs fits certain people, people who like to do everything in one place.
Sometimes I think Emacs is for people who're using poor window manager. Because if you're using something like Gnom's default metacity, it's hard to create a new console, do something there while reading stuff in your text editor, then switch back to your editor. In short, most window managers doesn't allow you to manipulate layout between your editor and task windows easily. But if you're using tiling window manager like XMonad, I think Vim is the best fit because you can always do something in a new window easily while looking at your editor.
Emacs is cool. I just like Vim more.
Aug 25, 2010
Find missing git ref
I was a fool this morning: I rsynced old source code from my macbook to my new thinkpad w510. I have been working on the new thinkpad since Tuesday, without a push to github (ye, fool again), so all recent works exist only on thinkpad. After the rsync, I found the last commit in my git repo is committed 2 days ago ..
After a period of a mix of jump/cry/smoke/hit walls with my head/... I calmed down. Git saves any new file after you commit, it also save the tree and commit as object files, then it modify the ref to point to the new commit file. Rsync only ruined my refs, overwrite them to point to the old commit file, but the new source file, tree, commit should be still there on my dear harddisk. If I can find the last commit file of yesterday, then modify the ref to that commit manually, I may get all my changes back!
First I need to list all object files related to the yesterday's last commit. A while later I find them with:
The result is like this:
The next step is to check the contents and find the commit in these object files. I tried with `git cat-file` first, but it just report "fatal: Not a valid object name 3fc43a817252e031f6d0c387930539b4c613bc" again and again, because the new object is not in the old repo really.
After a google around I found a one-liner python script to inspect the content of object file, that's what I need exactly:
Next is easy: I just checked each object file manually, and found the lovely commit object file at the 9th try:
The file name of the commit is ./objects/bb/a640a7830fafa3d9ae352a2b060df600a4d5e7, so I just modified the content of refs/head/branch-name to bba640a7830fafa3d9ae352a2b060df600a4d5e7.
The last step is go back to the repo, clean the repo with 'git reset --hard' because the files are still in old revision. Then everything just come back!
After a period of a mix of jump/cry/smoke/hit walls with my head/... I calmed down. Git saves any new file after you commit, it also save the tree and commit as object files, then it modify the ref to point to the new commit file. Rsync only ruined my refs, overwrite them to point to the old commit file, but the new source file, tree, commit should be still there on my dear harddisk. If I can find the last commit file of yesterday, then modify the ref to that commit manually, I may get all my changes back!
First I need to list all object files related to the yesterday's last commit. A while later I find them with:
cd .git
find . -newer <the newest file in current corrupted repo> -type f | xargs ls -l | grep object | grep "Aug 25 19:09" | awk '{print $9}'
The result is like this:
./objects/0d/34526c4149e4c89c436a058c66d1b69850dcea
./objects/0d/3d1caf38f65e6b7f2b7b693d721b66c6cda45d
./objects/0e/e7efbe5eeb7a320c09046011e9fc5e10e51a88
./objects/36/d3fdab703e5e080bf63bb76c069fa51a456a24
./objects/59/3371c18e1657d786265b46deb747f3d8cc8d00
./objects/76/3da4c776fae22d4cbee789703790f81fcfaed5
./objects/a0/9a140235ce52747157a6b199c99a464a5545a4
./objects/b1/a080cda86596501ee5bd88181c89fae1d5f07d
./objects/bb/a640a7830fafa3d9ae352a2b060df600a4d5e7
./objects/cb/ddce9d6079a720e13492c4ea055fb61b6e908b
./objects/e3/5a4ba7d374dd96f70a763d128ac849be173b86
The next step is to check the contents and find the commit in these object files. I tried with `git cat-file` first, but it just report "fatal: Not a valid object name 3fc43a817252e031f6d0c387930539b4c613bc" again and again, because the new object is not in the old repo really.
After a google around I found a one-liner python script to inspect the content of object file, that's what I need exactly:
python -c 'import sys,zlib; sys.stdout.write(zlib.decompress(open(sys.argv[1]).read()))' <path-to-object-file>
Next is easy: I just checked each object file manually, and found the lovely commit object file at the 9th try:
commit 232tree b1a080cda86596501ee5bd88181c89fae1d5f07d
parent 09f4a0cd1374d848bffffba6c02fa6830aea587a
author Jan <j@xxxxxxxx.xx> 1282734563 +0800
committer Jan <j@xxxxxxxx.xx> 1282734563 +0800
The file name of the commit is ./objects/bb/a640a7830fafa3d9ae352a2b060df600a4d5e7, so I just modified the content of refs/head/branch-name to bba640a7830fafa3d9ae352a2b060df600a4d5e7.
The last step is go back to the repo, clean the repo with 'git reset --hard' because the files are still in old revision. Then everything just come back!
Jul 1, 2010
Universal Quantification, Bound and Existential Quantification
Universal quantification is usually not very useful. Inside the body of a universal quantified function, what you know about the argument is very general, because the argument can be *any* type. Suppose you're writing a function with type *->Int, what do you think the function can do? The only implementation I can think of is a constant function:
(pseudo codes)
In contrast, existential quantified functions are very useful, because there're always *some* types can do certain things. Use the same example:
I can do nearly anything inside f2, because there's always some x will satify the operations applied on them.
You should notice that only functions or Bottom can have universal quantified type.
Bound helps universal quantification a lot. When you give a bound to universal quantification, you give it extra informations.
(pseudo codes)
f1 :: [forall a] a -> Int
f1 x = 1
In contrast, existential quantified functions are very useful, because there're always *some* types can do certain things. Use the same example:
f2 :: [exist a] a -> Int
f2 x = length x
I can do nearly anything inside f2, because there's always some x will satify the operations applied on them.
You should notice that only functions or Bottom can have universal quantified type.
Bound helps universal quantification a lot. When you give a bound to universal quantification, you give it extra informations.
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