Is it possible to create a completely self-contained bash script that does not require manual typing?

Question

linux

Is it always possible to create a bash script to run without input at all?
That is, I want to create such a new_os_init.sh, so that it installs everything I need, creates a user, a group, configures visudo .... in short, everything that I am currently doing manually on a new server.
Is this always possible or at least sometimes, but you still need to enter something with your hands?
If always, then in which direction to dig: how to make him 1) answer yes 2) choose the answer option that I need, etc.
Of course, I know in advance what to answer where.

Answer 1

Can.

Answer 2

Most linux utilities can work in "script" mode (eg parted -s ... ), that is, automatically accept a given response or default action (eg rm -f ... delete without confirmation).
In extreme cases, you can find utilities that can do this. For example, to set a password after creating a user, instead of passwd , you can use chpasswd : If the utility does not support script mode and there are no suitable replacements, then you can use the expect utility , which Konstantin wrote about earlier.

Answer 3

Can.
The simplest option is to read the help about command line arguments, many commands can be given all the necessary data at startup.
Read more about redirects. For example, for a command like

$ command
press "yes" to continue
(вводим yes)
completed
$

In an automation script, you can do

command <<EOF
yes
EOF

echo yes > answers.txt
command <answers.txt

Answer 4

Not exactly pure bash, but lets you do without those bikes:
ansible

Answer 5

You can :)
To interact with interactive requests, there is a program expect.
Very detailed with examples of expect is described on Habré .