The Amazon Web Services (AWS) command-line interface — the AWS Cli — lets you update the code of a Lambda function right from the cli. Here's how.
aws lambda update-function-code \
--function-name my-function-name \
--region us-west-2 \
--zip-file fileb://lambda.zip
Let's understand what you need to run this command.
aws lambda update-function-code - to execute this command you need the awscli installed on your machine and your authentication information has to be configured to your account--function-name - this is the name of an existing Lambda function in your AWS account--region - the region in which your Lambda lives (in this case, it's Oregon, whose code is us-west-2, you can see a list of regions and their codes here)--zip-file - this is the path to your zipped Lambda code with the fileb:// prefix, in the example, there's a lambda.zip file in the current directory, alternatively you can use the --s3-bucket and --s3-key to use a zip file from an S3 bucket)After your function code has been updated, you can invoke the Lambda function to verify everything is working as expected.
If you want to learn more about this command, here's the AWS CLI command reference guide, and here's the free Kindle version. Among other things, it lets you create Lambda Layer versions, invoke functions, and much more.