Shell Programming and Scripting

Hi All,

In our code we are using below code to calculate the UNIX Epoch Time from the time stamp present in the file.
Can any one explain how the DC operates in below command and how we calculate the UNIX EPOCH time from this.

Date incide the file is 20:26:51
Output we get is 1289943554


File content:

0|0|4|472|2010-11-15 23:22:14|2010-11-15 23:30:06
0|0|3|200|2010-11-15 20:26:51|2010-11-15 20:30:11

Thanks.

@mithunpatel
We assume you mean the unix "dc" (desktop calculator) program.
Please post the script.

Code:

filetime=`cpio -o 2> /dev/null << EOF | od -x | sed '1d
s/[^ ]* *\(....\) *\(....\).*/16i\1\2p/;y/abcdef/ABCDEF/;q'|dc
$filedir/$dirlist/$filelist
EOF`

---------- Post updated at 08:39 AM ---------- Previous update was at 08:36 AM ----------

@methyl
Yes I mean unix DC program.
Also please explain how the "od" command plays the significance and how DC gets the above out put. I was wondering what was the purpose of "od" here.

This is possibly the most obfuscaded code I have ever seen.

I think this needs a "sed" expert (not me).

As far as I can see the script is creating a cpio archive of a file to a pipeline, displaying the archive in formatted hexadecimal (the "od -x") then fishing the formatted file modifiction date out of the archive and then converting that date from hexadecimal to decimal. I could be wrong.

On my system the cpio header structure is described in "man 4 cpio".

The approach is interesting but a "tar" archive format might have been easier to work with.

There are much better methods depending on what Operating System you have.