Below are easy install instructions by OS and Architecture. As always there are always the standard instructions in the README.md as well.
linux
386 - linux
# Export the sha256sum for verification.
$ export NETNS_SHA256="be81bc3fa68c7c9892a0b84e6429e2af5be58e74474f0dcddad78647dd741ce7"
# Download and check the sha256sum.
$ curl -fSL "https://github.com/genuinetools/netns/releases/download/v0.5.3/netns-linux-386" -o "/usr/local/bin/netns" \
&& echo "${NETNS_SHA256} /usr/local/bin/netns" | sha256sum -c - \
&& chmod a+x "/usr/local/bin/netns"
$ echo "netns installed!"
# Run it!
$ netns -h
amd64 - linux
# Export the sha256sum for verification.
$ export NETNS_SHA256="8a3a48183ed5182a0619b18f05ef42ba5c4c3e3e499a2e2cb33787bd7fbdaa5c"
# Download and check the sha256sum.
$ curl -fSL "https://github.com/genuinetools/netns/releases/download/v0.5.3/netns-linux-amd64" -o "/usr/local/bin/netns" \
&& echo "${NETNS_SHA256} /usr/local/bin/netns" | sha256sum -c - \
&& chmod a+x "/usr/local/bin/netns"
$ echo "netns installed!"
# Run it!
$ netns -h
arm - linux
# Export the sha256sum for verification.
$ export NETNS_SHA256="66e102dcae447898571fa3df344ebf530d27134ceb41a86d2498669e57053124"
# Download and check the sha256sum.
$ curl -fSL "https://github.com/genuinetools/netns/releases/download/v0.5.3/netns-linux-arm" -o "/usr/local/bin/netns" \
&& echo "${NETNS_SHA256} /usr/local/bin/netns" | sha256sum -c - \
&& chmod a+x "/usr/local/bin/netns"
$ echo "netns installed!"
# Run it!
$ netns -h
arm64 - linux
# Export the sha256sum for verification.
$ export NETNS_SHA256="4ff0e3ede6ca43eadbf5229b8b51228266a08d5a755e8bae822859b9488d12bd"
# Download and check the sha256sum.
$ curl -fSL "https://github.com/genuinetools/netns/releases/download/v0.5.3/netns-linux-arm64" -o "/usr/local/bin/netns" \
&& echo "${NETNS_SHA256} /usr/local/bin/netns" | sha256sum -c - \
&& chmod a+x "/usr/local/bin/netns"
$ echo "netns installed!"
# Run it!
$ netns -h