How to search an expression in a file from a bash script?

Question

I have a bash script. I need to look if "text" exists in the file and do something if it exists.

Thanks in advance

Answer 1

grep is your friend here

Answer 2

Something like the following would do what you need.

grep -w "text" file > /dev/null

if [ $? -eq 0 ]; then
   #Do something
else
   #Do something else
fi

Answer 3

cat <file> | grep <"text"> and check the return code with test $?

Check out the excellent: Advanced Bash-Scripting Guide

Answer 4

If you need to execute a command on all files containing the text, you can combine grep with xargs. For example, this would remove all files containing "yourtext":

grep -l "yourtext" * | xargs rm

To search a single file, use if grep ...

if grep -q "yourtext" yourfile ; then
  # Found
fi

Answer 5

You can put the grep inside the if statement, and you can use the -q flag to silence it.

if grep -q "text" file; then
    :
else
    :
fi

Answer 6

just use the shell

while read -r line
do
  case "$line" in
   *text* ) 
        echo "do something here"
        ;;
   * )  echo "text not found"
  esac
done <"file"