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Problem with sed

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# 15  
Old 09-25-2011
AFAIK, I don't think sed recognizes any column.

--ahamed
# 16  
Old 09-25-2011
What about grep, or awk? Is there anything I can do?
# 17  
Old 09-25-2011
you need to add something in the 3rd row 10th column? How do you separate the column? space?
And do you have a pattern? I mean is it always at the 3rd row?

--ahamed

---------- Post updated at 02:04 PM ---------- Previous update was at 01:45 PM ----------

I really don't know what you are trying to accomplish. The following code will add blank lines and then insert the value at the specified row.

Code:
val=123
row=5
awk -v row=$row -v file=file ' BEGIN{cmd="wc -l " file;cmd|getline;new_line=row-$1; while(new_line>0){print "" >> file;new_line--;}} ' file 
&& sed -i "$row i $val" file

--ahamed
Last edited by ahamed101; 09-25-2011 at 05:56 PM..
# 18  
Old 09-25-2011
Well the idea is that im creating a paint program. So the file starts as a canvas of black escape codes. So here is what the input file would look like:

Code:
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m

So the idea is that, when the user paints a different colored pixel, one of the escape codes on the canvas have to change.

So how can I use sed to go to a certain line, and move to a certain column to replace one of the black escape codes like for example, replace with a blue escape code.

Here is the desired output. I want to save the blue escape code on the 3rd line of the canvas, On the 5th column of escape codes. Like so:

Code:
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;45m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m
\E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m \E[0;40m

# 19  
Old 09-25-2011
The sed statement itself is correct. It just needs an input file:
Code:
sed "${row} s/./${newchar}/${col}" infile > test.txt

and the input file would have to contain the rows and column values..
Last edited by Scrutinizer; 09-25-2011 at 06:17 PM..
# 20  
Old 09-25-2011
Something like this?
Code:
awk -v row=3 -v col=5 -v val='\\E[0;45m' '{if(NR==row){$col=val}}1' input_file > new_file

--ahamed
# 21  
Old 09-25-2011
ahamed101, I don't know why your codes not working. Seems legit though.
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