bash script check strings in file

Question

How do I do something like:

if !("abc" in file1 and "def" in file2)
then
  echo "Failed"
fi

I've already known how to check "abc" in file1: grep -Fxq "abc" file1 , but I can't manage to get the if not (command1 and command2) part to work.

Answer 1

You got it almost right. Just add a space between the exclamation mark and the grep commands, and it would work:

if ! (grep -Fxq "abc" file1 && grep -Fxq "def" file2); then
     echo "Failed"
fi

Assuming bash , there is no need for extra else .

Note that using parenthesis runs the greps in a subshell environment, as a child shell process. You can easily avoid this by using curly braces (this thing is called group command):

if ! { grep -Fxq "abc" file1 && grep -Fxq "def" file2; }; then
     echo "Failed"
fi

Note that you need more spaces and an additional semicolon – isn't bash syntax just so funny!?!

Answer 2

You could do:

$ grep -Fxq "abc" file1 && grep -Fxq "def" file2 || echo "Failed"

This uses the bash logical operators AND && and OR || .

This can be split over multiple lines like:

$ grep -Fxq "abc" file1 && 
> grep -Fxq "def" file2 ||
> echo "Failed" 

Answer 3

if (grep -Fxq "abc" file1 && grep -Fxq "def" file2);
then
  echo ""
else
  echo "failed"
fi