Question

I have an input like following.

Curveplot
Time
Maxima of Curve
Part no.
13 #pts=2
* Minval=   0.000000e+000 at time=        0.000000
* Maxval=   2.237295e+000 at time=        0.001000
   0.000000e+000       0.000000e+000
   9.999999e-004       2.237295e+000
endcurve

I want to take get the maximum value out of this file, which is the value after Maxval

* Maxval=   2.237295e+000 

Can someone suggest how to do it with linux sed ?
My output would only be the number 2.237295e+000.

Answer 1

Using the following one-liner will only display 2.237295e+000

sed -nr 's/.*Maxval= *([^ ]*).*/\1/p'

Regex:

Match:
.*      # match any characters
Maxval= # upto 'Maxval='
 *      # match multiple spaces (that is a space followed by *)
([^ ])  # match anything not a space, use brackets to capture (save this) 
.*      # match the rest of line

Replace with:
\1      # the value that a was captured in the first set of brackets. 

So effectively we substitute the whole line containing the word Maxval= by the value of Maxval.

Note: depending on the platform and/or implementation of sed the you may need to use -E instead of -r.