How to delete from a text file, all lines that contain a specific string?

Question

How would I use sed to delete all lines in a text file that contain a specific string?

Answer 1

There are many other ways to delete lines with specific string besides sed:

AWK

awk '!/pattern/' file > temp && mv temp file

Ruby (1.9+)

ruby -i.bak -ne 'print if not /test/' file

Perl

perl -ni.bak -e "print unless /pattern/" file

Shell (bash 3.2 and later)

while read -r line
do
  [[ ! $line =~ pattern ]] && echo "$line"
done  o
mv o file

GNU grep

grep -v "pattern" file > temp && mv temp file

And of course sed (printing the inverse is faster than actual deletion):

sed -n '/pattern/!p' file