cloud engineer
by Ulysses
Here’s a quick way to start a web server using Python (not recommended for production).
If you want to use python3, you may have to use explicitly use python3.
Check what versions you have first.
python --version python3 --version |
python --version python3 --version
Start web server using port 8080 in the current directory.
python -m http.server 8080 |
python -m http.server 8080
If you want an alternate directory, use this -d option.
python -m http.server 8080 -d /tmp |
python -m http.server 8080 -d /tmp
It’s a great tool for quick downloads.
by Ulysses
If you have a file with @ sign at end, this is how to remove extended attributes on the Mac OS.
Example.
ls -l -rwxr-xr-x@ 4 username staff 128 Mar 24 10:51 sample.txt |
ls -l -rwxr-xr-x@ 4 username staff 128 Mar 24 10:51 sample.txt
Remove extended attributes.
xattr -c sample.txt |
xattr -c sample.txt
Result
ls -l -rwxr-xr-x 4 username staff 128 Mar 24 10:51 sample.txt |
ls -l -rwxr-xr-x 4 username staff 128 Mar 24 10:51 sample.txt
by Ulysses
Here’s the script to backup GCP disks.
#!/bin/bash now=$(date +%s) disks=$(gcloud compute disks list --project project-id --filter="users:instance" --format="value(name)") for disk in $disks do gcloud compute disks snapshot $disk \ --snapshot-names=$disk-$now \ --zone=us-central1-a \ --project=project-id \ --async done |
#!/bin/bash now=$(date +%s) disks=$(gcloud compute disks list --project project-id --filter="users:instance" --format="value(name)") for disk in $disks do gcloud compute disks snapshot $disk \ --snapshot-names=$disk-$now \ --zone=us-central1-a \ --project=project-id \ --async done
by Ulysses
How to do search and replace in Vim.
Search for “foo” and replace it with “bar” in the current line. Use :s
:s/foo/bar/g |
:s/foo/bar/g
Search for “foo” and replace it with “bar” in the entire document. Use :%s
:%s/foo/bar/g |
:%s/foo/bar/g
You can also pipe instead of forward slash. Useful if your search contains a /.
:%s|foo/|bar|g |
:%s|foo/|bar|g
by Ulysses
In Redhat 8, every time you the Network Manager get’s restarted it overwrites /etc/resolv.conf. To prevent that from hapenning, create a new file called /etc/NetworkManager/conf.d/90-dns-none.conf and add the following lines. Restart Network Manager. Your /etc/resolv.conf should be unchanged.
[main] dns=none |
[main] dns=none
Restart Network Manager
$ systemctl reload NetworkManager |
$ systemctl reload NetworkManager
by Ulysses
How to list S3 objects using Python Boto3
import boto3 from sys import argv bucket=argv[1] s3 = boto3.resource('s3') mybucket = s3.Bucket(bucket) def list_buckets(): print("List of Buckets: ") for bucket in s3.buckets.all(): print(bucket.name) def list_files(): print("Buckets: The objects in the \"" + bucket + "\" buckets are ... ") for files in mybucket.objects.all(): print(files.key) def main(): #list_buckets() list_files() if __name__ == "__main__": main() |
import boto3 from sys import argv bucket=argv[1] s3 = boto3.resource('s3') mybucket = s3.Bucket(bucket) def list_buckets(): print("List of Buckets: ") for bucket in s3.buckets.all(): print(bucket.name) def list_files(): print("Buckets: The objects in the \"" + bucket + "\" buckets are ... ") for files in mybucket.objects.all(): print(files.key) def main(): #list_buckets() list_files() if __name__ == "__main__": main()
Running command
$ python test.py bucket-name # with python $ ./test.py bucket-name # without python |
$ python test.py bucket-name # with python $ ./test.py bucket-name # without python
Results
Buckets: The objects in the "bucket-name" are .... abc.txt def.txt |
Buckets: The objects in the "bucket-name" are .... abc.txt def.txt
by Ulysses
How to create a Python virtual environment.
On Windows
$ pip install venv $ python3 -m venv ~/python-test |
$ pip install venv $ python3 -m venv ~/python-test
On Ubuntu
$ sudo apt install python3.8-venv $ python3 -m venv ~/python-test |
$ sudo apt install python3.8-venv $ python3 -m venv ~/python-test
On Mac OS
$ brew install virtualenv
$ virtualenv python-test |
$ brew install virtualenv $ virtualenv python-test
Activate
$ cd ~/python-test $ source bin/activate |
$ cd ~/python-test $ source bin/activate
Deactivate
$ deactivate |
$ deactivate
by Ulysses
How to reformat numbers in Bash.
$ n=1023555 $ m=$(numfmt --to=si n) $ echo $m 1.1M |
$ n=1023555 $ m=$(numfmt --to=si n) $ echo $m 1.1M
Other options
--to=none # no scaling. Output: 1023555 --to=si # International System of Units (SI) standard. Output 1.1M --to=iec # International Electrotechnical Commission (IEC) standard. Output: 1.1Mi --to=iec-i # International Electrotechnical Commission (IEC) standard. Output: 1.1M --to=auto # ‘auto’ can only be used with --from. |
--to=none # no scaling. Output: 1023555 --to=si # International System of Units (SI) standard. Output 1.1M --to=iec # International Electrotechnical Commission (IEC) standard. Output: 1.1Mi --to=iec-i # International Electrotechnical Commission (IEC) standard. Output: 1.1M --to=auto # ‘auto’ can only be used with --from.