Posted on

Display file permissions as octal number in ls command

Normally, in *nix systems like Linux, mac the file permissions are displayed as symbolic notations. So when doing a ls -l in a directory you’ll see drwxr-xr-x+ like symbolic permissions next to a directory. This is equivalent to 755 in octal permissions. I find octal permissions easier to grasp and understand. Unfortunately, there is no native switch in ls to show octal permissions. So here is a little custom command that will do the needful.

[code lang=”bash”]
ls -l | awk ‘{k=0;for(i=0;i<=8;i++)k+=((substr($1,i+2,1)~/[rwx]/)*2^(8-i));if(k)printf("%0o ",k);print}’
[/code]

This command will show octal file permissions before its symbolic representation.

If you find it impressive and would like to bookmark it, just add this line in your ~/.profile or ~/.bash_profile (depending on mac or linux) using your favorite editor (I’d use vim).

[code lang=”bash”]
alias l= "ls -la | awk ‘{k=0;for(i=0;i<=8;i++)k+=((substr(\$1,i+2,1)~/[rwx]/)*2^(8-i));if(k)printf(\" %0o \",k);print}’"
[/code]

We have just escaped $ and " with a \ in above line.

Some under-the-hood details: This command works by piping the output of ls -l to awk as its input. awk is a pattern directed scanning and processing language. For more info you can do man awk which shows:

Awk scans each input file for lines that match any of a set of patterns specified literally in prog or in one or more files specified as -f progfile. With
each pattern there can be an associated action that will be performed when a line of a file matches the pattern. Each line is matched against the pattern
portion of every pattern-action statement; the associated action is performed for each matched pattern. The file name – means the standard input. Any file
of the form var=value is treated as an assignment, not a filename, and is executed at the time it would have been opened if it were a filename. The option
-v followed by var=value is an assignment to be done before prog is executed; any number of -v options may be present. The -F fs option defines the input
field separator to be the regular expression fs.

An input line is normally made up of fields separated by white space, or by regular expression FS. The fields are denoted $1, $2, …, while $0 refers to
the entire line. If FS is null, the input line is split into one field per character.

A pattern-action statement has the form

pattern { action }

A missing { action } means print the line; a missing pattern always matches. Pattern-action statements are separated by newlines or semicolons.

Posted on

MAC View file transfer speeds while copying

Often while copying large files from external hard disks, you want to see the transfer rates. MAC natively doesn’t show the transfer speed. However there’s a workaround:

1) open Terminal and write:

[code lang=”bash” light=”true”]
while true ; do iostat -w 2 ; done
[/code]

This will show real-time data transfer speed of all mounted disks. Like:
[code lang=”bash” light=”true”]
$ while true ; do iostat -w 2 ; done
disk0 disk1 cpu load average
KB/t tps MB/s KB/t tps MB/s us sy id 1m 5m 15m
71.23 134 9.35 44.69 45 1.96 21 22 58 1.61 1.94 1.90
70.61 237 16.33 66.18 169 10.95 8 30 63 1.48 1.91 1.88
77.30 109 8.22 16.09 605 9.50 8 33 59 1.48 1.91 1.88
385.81 20 7.53 21.54 449 9.44 8 28 64 1.44 1.89 1.88
243.28 17 4.04 14.09 319 4.39 7 26 67 1.44 1.89 1.88
[/code]

Posted on

HTML encode text in javascript simple shortcut

Recently, I wanted to obfuscate HTML text for some reasons. I found this link http://www.voormedia.com/en/tools/html-obfuscate-scrambler.php
for scrambling text.

My HTML document was:

[code lang=”html”]
<div id=”pictures”>
<h2>Exterior</h2>
<a class=”hyperlinks” href=”link”> link1 inside Exterior</a>
<a class=”hyperlinks” href=”link”> link2 inside Exterior</a>
<a class=”hyperlinks” href=”link”> link3 inside Exterior</a>
<h2>Interior</h2>
<a class=”hyperlinks” href=”link”> link1 inside Interior</a>
<a class=”hyperlinks” href=”link”> link2 inside Interior</a>
<a class=”hyperlinks” href=”link”> link3 inside Interior</a>
<a class=”hyperlinks” href=”link”> link4 inside Interior</a>
<h2>Specific text 3</h2>
<a class=”hyperlinks” href=”link”> link1 inside specific text 3</a>
<a class=”hyperlinks” href=”link”> link2 inside specific text 3</a>
</div>
[/code]

The obfuscated code generated by http://www.voormedia.com/en/tools/html-obfuscate-scrambler.php:

[code lang=”js”]
<script type=”text/javascript” language=”JavaScript”>
var i,y,x=”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”;
y=”;
for(i=0;i<x.length;i+=2)
{y+=unescape(‘%’+x.substr(i,2));}
document.write(y);
</script>
[/code]

Basically the obfuscation script thinly disguised each character as hexadecimal value and puked out the unescaped version via a simple document.write js call.

Now, I decided to deobfuscate this obfuscated code. For this, I needed to HTML encode the value of “y” before passing it to document.write(). To my surprise, there is no native HTML encode function in javascript. Apparently, there is not much use of HTML encode function as its assumed that all HTML encoding comes from server side itself. But you can clearly feel its requirement if you are a pro developer, as illustrated in this example here.

Fortunately, a tweaked version of HTML encode can be constructed by appending normal unescaped string inside text node of a psuedo div element. Then returning the innerhtml of this div.
Here is the function code:

[code lang=”js”]
<script type=”text/javascript” language=”JavaScript”>
function HTMLencode(value)
{
var div = document.createElement(‘div’);
var text = document.createTextNode(value);
div.appendChild(text);
return div.innerHTML;
}
</script>
[/code]

Finally, here’s the complete code to deobfuscate:

[code lang=”js”]
<script type=”text/javascript” language=”JavaScript”>
function HTMLencode(value)
{
var div = document.createElement(‘div’);
var text = document.createTextNode(value);
div.appendChild(text);
return div.innerHTML;
}

var i,y,x=”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”;
y=”;
for(i=0;i<x.length;i+=2)
{y+=unescape(‘%’+x.substr(i,2));}
document.write(HTMLencode(y));
</script>
[/code]