Bash - remove all lines beginning with 'P'

Question

I have a text file that\'s about 300KB in size. I want to remove all lines from this file that begin with the letter \"P\". This is what I\'ve been using:

&g         


        

Answer 1

Use sed with inplace substitution (for GNU sed, will also for your cygwin)

sed -i '/^P/d' file.txt

BSD (Mac) sed

sed -i '' '/^P/d' file.txt