curl command runs on terminal but doesnt run on.sh script

[Manish Amatya]

when i run following command on terminal it works and post value the the issue but when i run the same command from .sh script file it doesnt work and gives out error 

curl --insecure -u "username":$cat(password.txt) -X PUT --data '{"fields" : {"customfield_10301" : "value"} }' -H "Content:application/json" https://url/rest/api/2/issue/(issueid)

it give following error

cat password.txt command not found

curl --insecure -u "username":$cat(password.txt) -X PUT --data '{"fields" : {"customfield_10301" : "value"} }' -H "Content:application/json" https://url/rest/api/2/issue/(issueid : No such file or directory