How to grep a string after a specified line number?
Alternatively you can use sed.sed can be used to mimic grep like this:
sed -n 's/pattern/&/p'
By default sed prints every line even if no substitution occurs. The combinations of -n and /p makes sed print only the lines where a substitution has occured. Finally, we replace pattern by & which means replace pattern by itself. Result: we just mimicked grep.
Now sed can take a range of lines on which to act. In your case:
sed -n '50000,$s/time spent/&/p' myfile.txt
The format to specify the range is as follow: start,endWe just instruct sed to work from line 50000 to $ which means last line.