Bash Functions

compareHash.sh

#!/bin/bash
#compareHash(){
    if [[ -f $1 ]]; then # $1 should always be a file
	   if [[ -f $2 ]]; then
	       # $2 can be a file to be compared with $1 using sha256
	       [[ $(sha256sum "$1" | cut -d ' ' -f 1) == "$(sha256sum "$2" | cut -d ' ' -f 1)" ]] && echo "Both files are same." || echo "Files are different."
	   else
	       # $2 can be a string containing the hash to be checked for $1
	       hash=$2
		   if [[ ${#hash} == 32 ]]; then
		      fileHash=$(md5sum "$1" | cut -d ' ' -f 1)
#		      export fileHash
		   elif [[ ${#hash} == 40 ]]; then
		      fileHash=$(sha1sum "$1" | cut -d ' ' -f 1)
#		      export fileHash
		   elif [[ ${#hash} == 64 ]]; then
		      fileHash=$(sha256sum "$1" | cut -d ' ' -f 1)
#		      export fileHash
		   else 
		      echo "$2 is not a valid argument";
			  exit 1
		   fi
		   [[ $fileHash == "$hash" ]] && echo "Checksum matches with provided file." || echo "Checksum does not match with provided file."
	   fi
	else
	   echo "$1 is not a valid file.";
	   exit 1
	fi
#}