Array operators

Shell Programming and Scripting
1

Hi

Lets say I have two arrays:
VAR_1 = "File_A" "File_B" "File_C" "File_D"
VAR_2 = "File_A" "File_D"

Is there a simple command to get the difference of these list, i.e.
VAR_1_2 = "File_B" "File_C"
or do I have to write a script and loop through all elements and compare them one by one?

Thanks

2

For most shell languages neither of those statements make an array. You cannot have spaces on any side of the = character:

bash array:

var_1=( "array element 1"  "array element 2")

ksh array:

set -A var_1 "array element 1"  "array element 2"

The answer to your question is No, there is no single command, you have to program a couple of pipes:

one way assuming you have the arrays already and they are array and array2:

echo ${array1[*]} | tr -s ' ' '\n' > file1
echo ${array2[*]} | tr -s ' ' '\n' > file2
diff file1 file2

I am assuming you want real differences. If you simply want to know if they are equal:

if [  "${array1[*]}" = "${array2[*]}"  ] ; then
   echo "same"
else 
  echo "different"
fi

Not sure what you wanted, really.

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