Checking if a multi-line string exist in a file - string

Question

I wanted to make a bash script to check if each line of multi-line string already exist in a file.
I had already wrote some code, but I'm not sure if it will work:
str="
this is
a multiple
line
string"
while read -r f; do
while read -r s: do
if [ $r == $s ]; then break; fi
done
done << some_file.txt
any ideas to get it working ?

Answer 1

Here's a trick if you can load the whole file twice to memory:
str="
this is
a multiple
line
string"
# Read the whole file in variable
content=$(<some_file.txt)
# Replace str to nothing in content
repr=${content/${str}}
# Check if it's the same.
if [[ "$content" != "$repr" ]]; then
# If it's not, means content contains str and it was removed.
echo "Contains"
fi

Answer 2

It can be a perl one-liner:
if perl -0777 -sne '/$text/ or exit 1' -- -text="$str" "$file"
then
echo Found
else
echo not found
fi
The -0777 option slurps the whole file into memory

Answer 3

This could be a solution in bash:
Reading the string lines into an array.
Then, for each string line in the array:
Checking the file contains a whole line equal to that string line.
Stop walking the array once a check fails.
#!/bin/bash
file="$1"
names="
this is
a multiple
line
string"
# Read string lines into an array
readarray -t <<< $names
# Walk array of lines
all_strings_found=true
for string in "${MAPFILE[#]}"; do
if ! grep -q "^$string$" $file; then
echo "'"$string"'" "not found"
all_strings_found=false
break
fi
done
if [ "$all_strings_found" == true ]; then
echo "---> All strings found"
else
echo "---> NOT all strings found"
fi

Answer 4

I like case statements for this.
$ cat script
str1="
this is
a multiple
line
string"
str2="$1"
f="$(<$0)"
case "$f" in
*"$str1"*) echo "String 1 exists" ;;
*) echo "String 1 not found" ;;
esac
case "$f" in
*"$str2"*) echo "String 2 exists" ;;
*) echo "String 2 not found" ;;
esac
$ ./script esac
String 1 exists
String 2 exists
$ ./script foo
String 1 exists
String 2 not found