Merge pull request #428 from Hacking-the-Cloud/add/aws/general_knowle…

…dge/aws_cli_tips_and_tricks

Added AWS CLI Tips and Tricks article

content/aws/general-knowledge/aws_cli_tips_and_tricks.md

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+---
+author_name: Nick Frichette
+title: AWS CLI Tips and Tricks
+description: A collection of tips and tricks for using the AWS CLI.
+---
+
+# AWS CLI Tips and Tricks
+
+## Standard Input/Output Redirection with "-"
+
+!!! Warning
+    The following examples have been tested in [bash](https://www.gnu.org/software/bash/) and [zsh](https://zsh.sourceforge.io/). Functionality may vary in other shells. If you find these commands work in additional environments, please open a pull request to update this note.
+
+When working in an AWS environment, you may frequently need to view the contents of objects stored in S3. The traditional approach involves a two-step process: using [s3:cp](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/s3/cp.html) to download the file to your local machine, then using `cat` or a similar tool to view it. While effective, this method can clutter your local system with temporary files and may be slower than necessary.
+
+Fortunately, the AWS CLI allows us to simplify this process by using the `-` [character](https://www.baeldung.com/linux/dash-in-command-line-parameters) which represents standard input/output (STDIN/STDOUT). Using `-`, you can read or write file content directly from or to S3 without creating local copies.
+
+### Reading from S3
+
+To read the contents of an object stored in S3 without having to download it first, use the following command:
+
+```bash
+aws s3 cp s3://bucket-name/object-key -
+```
+
+Example:
+
+```bash
+nick@host:~$ aws s3 cp s3://hackingthecloud/content -
+hacking the cloud
+```
+
+### Writing to S3
+
+To upload content directly to an object in S3 without a temporary file, use this command:
+
+```bash
+echo "hacking the cloud" | aws s3 cp - s3://bucket-name/object-key
+```
+
+This command writes the specified text to an S3 object, again bypassing the need for a local file.
+
+## Modifying the CloudTrail Log User-Agent with `AWS_EXECUTION_ENV`
+
+!!! example "Shout-out"
+    Shout-out to [Christophe Tafani-Dereeper](https://christophetd.fr/) for showing me this.
+
+When making API calls to AWS, a `User-Agent` header is included in each request, containing details about the client making the request. Although it’s not possible to fully [customize](https://github.com/aws/aws-cli/issues/3990) this header, you can append information to it, which can be useful for tracking API calls in CloudTrail logs.
+
+One way to modify the `User-Agent` is by setting the `AWS_EXECUTION_ENV` environment variable, used by AWS SDKs to identify the execution environment. Tools like [grimoire](https://github.com/DataDog/grimoire) leverage this variable to append custom information to the `User-Agent` header, making API tracking more informative.