Recently I noticed we have 3 options to set environment variables:

1. export envVar1=1
2. setenv envVar2=2
3. env envVAr3=3

If there are other ways, please enlighten us.

When should I prefer one over the other? Please suggest guidelines.

As for shell compatibility, which is the most expansive (covers more shell dialects)?

I already noticed this answer but I wish to expand the question with env and usage preference guidelines.

Recently I noticed we have 3 options to set environment variables:

1. export envVar1=1
2. setenv envVar2 2
3. env envVar3=3

If there are any other ways, please enlighten us.

When should I prefer one over the other? Please suggest guidelines.

As for shell compatibility, which is the most expansive (covers more shell dialects)?

I already noticed this answer but I wish to expand the question with env and usage preference guidelines.