breaking up a file in bash

[cwl157]

Ok, another question, How do I break up a file in bash. I have an input file that has some stuff thats gonna be done to it. However, i need to distiguish between the stuff above the blank line and below it. Here is the input file:

y 10 x -11.2
x 7.65 Y 3.2
x 9.3 y 1.2
X -5.6 y 14.6
Y 4.6 x 2.7
Y 5.89 X 12.45
-1.2 -4.6
y -7.6 X 8.2
x y 2.3
Y x 4.5

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60%

so basically, i need everything above the blank line to be in one file and everything below the blank line to be in another file. Both the stuff above and below can be of varied line numbers. I saw the split command, i don't think that will work, i need something that detects the new line and then takes everything after it and appends it to a file. So when the Zoom part starts. Those lines need to be taken out of that file and put in another file. Anyone know how to do this?

[Franklin52]

This:

sed '/^$/q'

echoes the lines before the first blank line and

sed '1,/^$/d'

echoes the lines after the first blank line.


Regards

[drl]

Hi.

while read var
do
  TEST and write as appropriate
done

The key is detecting an empty line.

case 1: pure bash
use loop structure above, TEST could include
a. old style form for zero-length string or equality to null string, [ ]
b. new style form for string comparison, [[ ]]

case 2: bash with other utilities
use loop structure above, TEST is more general using grep

case 3: sed
as Franklin52 noted

case 4: csplit
designed for this kind of situation

See man pages bash, sed, csplit for details. Post code when you have questions ...cheers, drl

[cwl157]

thanks for the replies. I have one more question about sed. I have to be able to detect and remove comments from a file. A comment starts with a /* and ends with a */ i need to detect those and any lines between those and delete them. Thanks.

[Franklin52]

Have a read of this first:

http://tldp.org/LDP/abs/html/string-manipulation.html

Regards