Difference between "#!/usr/bin/env bash" and "#!/usr/bin/bash": Official Slackware book created by David Cantrell, Logan Johnson & Chris Lumens. Version 2.0 is a draft that is in development.
Because /usr/bin/env can interpret your $PATH, which makes scripts more portable.
#!/usr/bin/env bash #lends you some flexibility on different systems
Running a command through /usr/bin/env has the benefit of looking for whatever the default version
of the program is in your current environment.
Will only run your script if python is installed in /usr/local/bin.
#!/usr/bin/bash #gives you explicit control on a given system of what executable is called
$ apt-get install ca-certificates curl -y