Behavior Command Comment go to the beginning of the line ctrl+a go to the end of the line ctrl+e Save a output of a command to a env variable principle_arn=$(aws –profile perAdmin sts get-caller-identity –query Arn –output text) use a env variable ${principle_arn} replace character sed -e “s|PRINCIPAL_ARN|${principle_arn}|g” \assume-role-policy-template.json > assume-role-policy.json The delimiter of choice is a forward slash (/), which is the most commonly used delimiter. However, sed can use any character as a delimiter. In fact, it will automatically use the character following the s as a delimiter-e means you can use the followed scripts multiple times.https://unix.stackexchange.com/questions/33157/what-is-the-purpose-of-e-in-sed-command