Shell Programming and Scripting

A=hello there;hello world;hello there world

CONST_A=`cat foo.txt | grep "A=" | cut -d "=" -f1`

hello there;hello world;hello there world

echo "A=hello there;hello world;hello there world" | sed '/hello there/s/^[a-zA-Z]*=//g'

CONST_A=$(sed -n '/A=/s/^.*=//p' foo.txt)
VAL_A="hellow there"

if [ "$CONST_A" = "$VAL_A" ]
then
   echo "Exact match"
fi
 
if [[ "$CONST_A" = *"$VAL_A"* ]]
then
    echo "$VAL_A is in the string"
fi

KEY=hello world;foobar;another

$ IFS='=' read -r key val <<< "$str"
$ echo "[[$key]] [[$val]]"
[[KEY]] [[hello world;foobar;another]]
$ IFS=';' read -ra vals <<< "$val"
$ declare -p vals
declare -a vals='([0]="hello world" [1]="foobar" [2]="another")'
$ in_array() { find=$1; shift; for v; do [[ $v = $find ]] && return 0; done; return 1; }
$ in_array foo "${vals[@]}"; echo $?
1
$ in_array foobar "${vals[@]}"; echo $?
0

$ VALS="hello world;foobar;another"
$ [[ ";$VALS;" = *";hello world;"* ]] && echo yes
yes

awk -F";" '
/^A=/ {
  for ( i=1; i<=NF; ++i ) {
    if (index($i, "hello world")>0 ) {
      print $i
    }
  }
}' foo.txt