Tag list source code.
Source
Monday, October 25, 2010
Shell word frequency filter
Also available here .
#!/bin/sh
# standard output.
#
# Usage:
# wf [ n]
tr -cs A-Za-z\' '\n'|
tr A-Z a-z |
sort |
uniq -c |
sort -k1,1nr -k2 |
sed ${1:-25}q
e.g.
cat fileName.txt | ./wf.sh 12
Description :
tr -cs A-Za-z\' ' \n' | Replace nonletters with newlines
tr A-Z a-z | Map uppercase to lowercase
sort | Sort the words in ascending order
uniq -c | Eliminate duplicates, showing their counts
sort -k1,1nr -k2 | Sort by descending count, and then by ascending word
sed ${1:-25}q Print only the first n (default: 25) lines;
$ wf 999999 < filename.txt | awk ' $1 >= 5' | wc -l
number of unique words occurring at least 5 times
$ wf 999999 < hamlet | tail -n 12 | pr -c4 -t -w80
some of the least frequent words
$ wf 999999 < hamlet | wc -l
number of unique words
$ wf 999999 < hamlet | grep -c ' ^ *1•'
or
number of words used exactly once
Source
#!/bin/sh
# standard output.
#
# Usage:
# wf [ n]
tr -cs A-Za-z\' '\n'|
tr A-Z a-z |
sort |
uniq -c |
sort -k1,1nr -k2 |
sed ${1:-25}q
e.g.
cat fileName.txt | ./wf.sh 12
Description :
tr -cs A-Za-z\' ' \n' | Replace nonletters with newlines
tr A-Z a-z | Map uppercase to lowercase
sort | Sort the words in ascending order
uniq -c | Eliminate duplicates, showing their counts
sort -k1,1nr -k2 | Sort by descending count, and then by ascending word
sed ${1:-25}q Print only the first n (default: 25) lines;
$ wf 999999 < filename.txt | awk ' $1 >= 5' | wc -l
number of unique words occurring at least 5 times
$ wf 999999 < hamlet | tail -n 12 | pr -c4 -t -w80
some of the least frequent words
$ wf 999999 < hamlet | wc -l
number of unique words
$ wf 999999 < hamlet | grep -c ' ^ *1•'
or
$ wf 999999 < hamlet | egrep -c '[[:space]]+1[[:space:]]+'
Source
Friday, October 22, 2010
tr shell command example
cat file(s) | tr A-Z a-z | tr -c a-z\' ' \n'
The second pipeline stage converts uppercase to
lowercase, the third replaces nonletters by newlines.
The third stage treats apostrophes as letters.
shell script for converting tab separated values to html table
# Convert a tab-separated value file to grammar-conformant HTML.
#
# Usage:
# tsv-to-html < infile > outfile
cat << EOFILE Leading boilerplate
<! DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN//3. 0">
<HTML>
<HEAD>
<TITLE>
Office directory
</TITLE>
<LINK REV="made" HREF="mailto: $USER@` hostname` ">
</HEAD>
<BODY>
<TABLE>
EOFILE
sed -e ' s=&=\& =g' \ Convert special characters to entities
-e ' s=<=\< =g' \
-e ' s=>=\> =g' \
-e ' s=\t=</TD><TD>=g' \ And supply table markup
-e ' s=^. *$= <TR><TD>&</TD></TR>='
cat << EOFILE Trailing boilerplate
</TABLE>
</BODY>
</HTML>
EOFILE
cut and awk for same job : extract fields and join them
$ cat test.txt
a:b:c:d:e
a1:b1:c1:d1:e1
Welcome@computer_1012 ~
$ cat test.txt | cut -d: -f1,5 --output-delimiter="-"
a-e
a1-e1
Welcome@computer_1012 ~
$ cat test.txt | awk -F: '{print $1 "-" $5}'
a-e
a1-e1
shell pattern matching
The problem is that the asterisks can match anything,
even the commas used as delimiters. However,
if you add the delimiters to the pattern, you can
no longer match the ends of the list:
list=orange, apple, banana
case $list in
*, orange, *) echo "The only fruit for which there is no Cockney slang. "; ;
esac
[no output]
To resolve this, wrap the list in an extra set of delimiters when expanding it:
list=orange, apple, banana
case , $list, in
*, orange, *) echo "The only fruit for which there is no Cockney slang. "; ;
esac
The only fruit for which there is no Cockney slang.
shell case switch
#! /bin/sh
pattern="$1"
shift
echo " Matching against ' $pattern' : "
for string
do
case $string in
$pattern) echo " $string: Match. " ; ;
*) echo "$string: No match. " ; ;
esac
done
Save this script to a file named pattern, make it executable (chmod a+x pattern), and you
can use it to perform your own tests:
$ ./pattern ' *' ' hello'
Matching against ' *' :
hello: Match.
$ ./pattern ' hello*' ' hello' ' hello, there' ' well, hello'
Matching against ' hello*' :
hello: Match.
hello, there: Match.
well, hello: No match.
Remember to use single quotes around the arg
shell command line looping (tested on cygwin)
% for file in *.bar ; do > echo $file >
mv $file `echo $file | sed 's/\.bar$/.foo/'` > done
% for file in `cat file_list` ; do > echo $file >
mv `echo $file | sed 's/\\r//'` `echo $file | sed 's/\.bar$/.foo/'` > done
Wednesday, October 20, 2010
The Pragmatic Programmer
4 key take-aways :
1. Design with concurrency in mind.
- i.e. assume that you are designing a multi threaded application
even though you may be designing a single threaded app.
It helps you to design cleanly and avoid temporal coupling.
Temporal coupling -> a;b; works but b;a; does not.
i.e. order of execution is critical.
An application designed in such a way(threadsafe) will
scale better, and if need be , can be adapted to multi-threaded
environments.
2. Get better at command line tools : awk/sed/gawk/for each/perl/grep etc.
3. Learn a new programming language every year
4. Read a technical book every quarter.
Tuesday, October 19, 2010
Thursday, October 14, 2010
Actionscript singleton class template IntelliJ Idea
Thanks to Gaurav Kushwaha, here is a singleton class template
for actionscript which you can use with Intellij Idea :
package ${PACKAGE_NAME}#if (${PACKAGE_NAME} != "") #end
{
public class ${NAME} #if (${Super_class_name} != "")extends ${Super_class_name}#end{
private static var _instance:${NAME};
public static function getInstance():${NAME} {
if (_instance == null) {
_instance = new ${NAME}(new Dummy());
}
return _instance;
}
public function ${NAME}(dummy:Dummy) {
}
}
}
class Dummy {
public function Dummy() {
}
}sorting lines with vim
For e.g.
test.txt :
z
y
x
w
v
u
If I say ->
:1,4 sort
test.txt will become
w
x
y
z
u
v
:.,+3 sort
will sort from current line to current line + 3.
:1,$ sort u
will sort and remove duplicates
To sort in reverse,
sort!
PS: This functionality doesn't work with IntelliJ Idea's vim plugin
To sort in reverse,
sort!
PS: This functionality doesn't work with IntelliJ Idea's vim plugin
Shell sample commands
Need to create a list of all the unique package names explicitly imported
by your Java code? The following stores it in a file called "list."
grep ' ^import ' *. j ava |
sed -e' s/. *import *//' -e's/; . *$//' |
sort -u >list
(sed -e is used for giving multiple commands to sed)
Shell sample commands
Which Java files have not been modified in the last week?
find . -name ' *. java' -mtime +7 -print
Which Java files have been modified in the last week?
find . -name ' *. java' -mtime -7 -print
Problems in running shell scripts on cygwin
I copied pasted this code :
#!/usr/bin/sh
N=1
while test "$N" -le "10"
do
echo "Number $N"
N=$[N+1]
done
in test.sh.
Then ran it like :
./test.sh
To get :
./test.sh: line 7: syntax error: unexpected end of file
Issue was that Windows/Dos files don't work well
as shell scripts, due to difference in new line formatting.
So, the solution is , dos2Unix convert command :
d2u test.sh
And, that's all.
Run happily ever after.
extracting social security number from an xml file using grep and cut
file.txt
<field10>123-45-6789</field10>
<field10>123-45-6789</field10>
<field10>123-4-6789-</field10>
here is the regexp
([0-9]+-)+[0-9]+<
and the command is
grep -o '\([0-9]\+-\)\+[0-9]\+<' file.txt | cut -d "<" -f 1
Wednesday, October 13, 2010
Linting php files from command line in Cygwin
$ ls -1 *.php | xargs -n1 ./php.exe -l | grep -i "errors parsing"
Executing vim commands from command line
Source
I executed the following when I wanted to replace
all "include" statements in my php files to "include_once"
vim.exe -c "argdo %s/include /include_once /ge | update" *.php
Friday, October 8, 2010
bookmarklet for changing a page's max size
javascript:(function(){var%20newSS,%20styles='body%20{max-width:%20800px;}';%20if(document.createStyleSheet)%20{document.createStyleSheet(%22javascript:'%22+styles+%22'%22);}%20else%20{newSS=document.createElement('link');%20newSS.rel='stylesheet';%20newSS.href='data:text/css,'+escape(styles);%20document.documentElement.childNodes[0].appendChild(newSS);}})();
Flex 4 difference between property and class
Source
Now, how do you know, regardless of the defnition style, which is a property
Now, how do you know, regardless of the defnition style, which is a property
and which is a class?
1: <s:Group>
2: <s:layout>
3: <s:VerticalLayout/>
4: </s:layout>
5: <s:Button label="1"/>
6: <s:Button label="2"/>
7: <s:Button>
8: <s:label>3</s:label>
9: </s:Button>
10: </s:Group>
The G in the <s: Group> tag is uppercase, so it refers to an instance of a Flex class named Group. The l in the <s:layout> tag is lowercase, so it is a property of the Group. The V in the <s:VerticalLayout> tag is uppercase, so it is referring to a new instance of a Flex class named VerticalLayout.Scrolling content in Flex 4
SourceIn previous versions of Flex, every container had this functionality by default. While extremely convenient for the developer, it also meant that
every container was burdened with this extra code even though it was hidden the vast majority of times. In Flex 4, you need to specificallyindicate when an area is scrollable. Tis is accomplished via a special tag named Scroller that wraps your Group tag.
1: <s:Scroller height="65">
2: <s:Group>
3: <s:layout>
4: <s:VerticalLayout/>
5: </s:layout>
6: <s:Button label="1"/>
7: <s:Button label="2"/>
8: <s:Button label="3"/>
9: </s:Group>
10: </s:Scroller>
Flex 4 basic layouts
Source 1: <s:Group> 2: <s:layout> 3: <s:HorizontalLayout/> 4: </s:layout> 5: <s:Button label="1"/> 6: <s:Button label="2"/> 7: <s:Button label="3"/> 8: </s:Group>HorizontalLayout/VerticalLayout/TileLayout/BasicLayout
AS-3/Flex Dictionary weak keys
A sample source code for using a dictionary in AS-3/Flex with weak keys.
When I say new Dictionary(true), after a while all those objects, whose
only references are as the dictionary keys, will be garbage collected.
So, if run the following in debug mode, after a while, output of trace
will be 0, from 1 initially.
1: <?xml version="1.0"?>
2: <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="init()">
3: <mx:Script><![CDATA[ 4: private var di:Dictionary = new Dictionary(true);
5: private function init():void {
6: di[new Sprite()] = [1,2,3];
7: setTimeout(startTrack,5000); 8: } 9: 10: private function startTrack():void {
11: System.gc(); 12: var count:int = 0;
13: for each (var arr:Array in di) {
14: ++count; 15: } 16: trace("number of elements in dictionary = " +count);
17: setTimeout(startTrack,5000); 18: } 19: ]]></mx:Script> 20: </mx:Application>Sunday, October 3, 2010
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