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Using shell to replace characters in a text file

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# 1  
Old 09-14-2011
Using shell to replace characters in a text file
Can I just say, this is such a frustrating and yet enormously rewarding field of study. I'm in the middle of configuring GeekTool (Uh oh, stupid n00b) and I really only have one question.

I'm using Automator to grab a RSS feed, having GeekTool continually run that application every 10 minutes, putting the results in a text file and then displaying that .txt file. However, the RSS codes their dates by their standards and I don't know how to intercept that and change them to my own time zone.

Here's a picture:

Image

Here's the GeekTool code that runs it:

Code:
head -n 300 ~/Documents/Notes/GeekTool/RSS/Cheatsheet.txt | tr '[\n]' '~' | sed 's/~~/\
/g' | sed 's/~//g' | sed 's/-0000//g'

----

Bonus question: Why is my script cutting off the text file at "NASA unveils ..."? There's plenty room in the window and the actual text file has more content than that. Is there a character limit cut-off that I'm missing in the code?

Thanks for reading!
# 2  
Old 09-14-2011
Without seeing the data which produced that, we're only guessing.
# 3  
Old 09-14-2011
Oh okay. What other information do you need? The automator script?

The code I copied and pasted above is what I put in the "Command" line of GeekTool. There isn't a separate Shell file beyond that.
# 4  
Old 09-14-2011
Give us the original input and desired output

--ahamed
# 5  
Old 09-16-2011
Okay. So basically I'm extracting from a xml feed and converting it to plain text on a locally stored file.

Image

So the .xml is saved and converted to a plain text file

Image

Now I use GeekTool and a Shell script to display that file on my desktop

Code:
head -n 300 ~/Documents/Notes/GeekTool/RSS/Cheatsheet.txt | tr '[\n]' '~' | sed 's/~~/\
/g' | sed 's/~//g' | sed 's/-0000//g'

Image

----

Now my question is how do I take these dates that were pulled from the xml file:

Image

and alter them using a Shell script to display my desired time?

My desired output would be the date converted to my time zone: Eastern Time Zone, (UTC−05). So basically the same format "yyyy-mm-dd hh:mm:ss" (remove the +0000) but just converted to my time. Can shell script do that?
# 6  
Old 09-16-2011
Something like this?
Code:
#!/bin/bash
while read line
do
  from_date=$( echo $line | sed -n 's/.* - \([0-9]*-.*\) +0000/\1/gp' )
  if [ ! -z "$from_date" ]
  then
    to_date=$( TZ=UTC date '+%F %k:%M:%S' -d "$from_date IST" )
    line=$( echo $line | sed "s/$from_date +0000/$to_date/g" )
  fi
  echo $line
done < inputFile


root@bt:/tmp# cat inputFile 
NEW DOLPHIN SPECIES DISCOVERED - 2011-09-16 13:09:00 +0000
IN AUSTRALIAN BAY
root@bt:/tmp# 
root@bt:/tmp# ./run
NEW DOLPHIN SPECIES DISCOVERED - 2011-09-16 7:39:00
IN AUSTRALIAN BAY
root@bt:/tmp#

And please try to paste the code in test format!

--ahamed
# 7  
Old 09-16-2011
Ahamed, I hope you're patient with me. I'm still learning so much. So I pasted in your code with my previous code to make this:

Code:
head -n 300 ~/Documents/Notes/GeekTool/RSS/Cheatsheet.txt | tr '[\n]' '~' | sed 's/~~/\
/g' sed 's/~//g' | sed 's/-0000//g'

#!/bin/bash
while read line
do
  from_date=$( echo $line | sed -n 's/.* - \([0-9]*-.*\) +0000/\1/gp' )
  if [ ! -z "$from_date" ]
  then
    to_date=$( TZ=UTC date '+%F %k:%M:%S' -d "$from_date IST" )
    line=$( echo $line | sed "s/$from_date +0000/$to_date/g" )
  fi
  echo $line
done < inputFile

root@bt:/tmp# cat inputFile 
NEW DOLPHIN SPECIES DISCOVERED - 2011-09-16 13:09:00 +0000
IN AUSTRALIAN BAY
root@bt:/tmp# 
root@bt:/tmp# ./run
NEW DOLPHIN SPECIES DISCOVERED - 2011-09-16 7:39:00
IN AUSTRALIAN BAY
root@bt:/tmp#

Now nothing displays. Maybe that's a GeekTool thing. In fact, maybe I should put your code in a separate .sh file and run that file instead of pasting both segments of the full code right into GeekTool like how I'm currently doing it. What do you think?
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