Shell script cheatsheet

shell.md

-z

-z to test if string is null (zero length)

if [ -z "$AWS_ACCOUNT_ID" ]; then
    echo "AWS_ACCOUNT_ID environment variable is not set."
    exit 1
fi

• Reference
• Reference - aws-app-mesh-example

set -e

• set -e to stop on first error (command return with non-zero retval).
• set +e to turn this off.
• Reference

Check command is present

check_command() {
  if ! [ -x "$(command -v "$1")" ]; then
    echo "$1 is required to run this script"
    exit
  fi
}

# usage
check_command aws

• Reference - aws-app-mesh-example