Unix-like System Commands

Record infrequently used but potential useful commands

1 Contents

iperf3 - Network speed test
qemu - convert images
base64 - encode & decode
smartctl - check macos ssd health
git-crypt - transparent file encryption in git

2 iperf3

Test network speed between devices. First, open server-side iperf/iperf3 service, then, test it by client-side iperf/iperf3 application. Under windows system, the application is iperf3.exe.

2.1 Open server-side iperf3 service

bash

iperf3 -s -p 5201

2.2 Open client-side iperf3 service

bash

iperf3 -c [ip address] -p 5201

3 Qemu convert images

bash

qemu-img convert -f [format] -O [output format] vm-114-disk-0.qcow2 vm-114-disk-0.raw

Example:

bash

# convert qcow2 to raw image
qemu-img convert -f qcow2 -O raw vm-114-disk-0.qcow2 vm-114-disk-0.raw

4 base64 encode and decode

encode:

bash

echo 'YourText' | base64

create pseudorandom number and encrypted by base64:

bash

head -c32 /dev/urandom | base64

decode:

bash

echo 'WW91clRleHQK' | base64 --decode

5 macos check ssd health

bash

smartctl -a [device id]

6 zfs send entire pool

bash

zfs snap pool_old@migrate
zfs send -Rv pool_old@migrate | zfs receive -F -d pool_new

7 zfs send dataset

bash

zfs snap pool/dataset@migrate
zfs send -R pool/dataset@migrate | zfs receive -F pool/dataset_new

8 git-crypt

9 git-crypt initialisation

Initialise to automatically create .git-crypt folder

bash

git-crypt init

Add public gpg key to project

bash

git-crypt add-gpg-user --trusted [your_email_or_key_id_or_fringerprint]

example:

bash

git-crypt add-gpg-user --trusted F278A3CCB6C173BD3660D173564D16856D20F3FC

Select files by adding .gitattributes file to automatic encrypt

git

# Encrypt
## Encrypt all files under vault
vault/** filter=git-crypt diff=git-crypt

## Make sure that .gitattributes is never encrypted.
.gitattributes !filter !diff
## Make sure that .gitignore is never encrypted.
.gitignore !filter !diff

10 common git-crypt usage

Only show the files required to encrypt

bash

git-crypt status -e

Remedies if git commit before encrypting

bash

git-crypt status -f