SHELL

add file to gitignore

touch .gitignore
$ git config --global core.excludesfile ~/.gitignore
$ echo '.idea' >> ~/.gitignore

git add gitignore

$ touch .gitignore

how to setup a gitignore

### Terraform ###
# Local .terraform directories
**/.terraform/*

# .tfstate files
*.tfstate

# Crash log files
crash.log

# Ignore any .tfvars files that are generated automatically for each Terraform run. Most
# .tfvars files are managed as part of configuration and so should be included in
# version control.
#
# example.tfvars

# Ignore override files as they are usually used to override resources locally and so
# are not checked in
override.tf
override.tf.json
*_override.tf
*_override.tf.json

# Include override files you do wish to add to version control using negated pattern
# !example_override.tf

# Include tfplan files to ignore the plan output of command: terraform plan -out=tfplan
# example: *tfplan*

# End of https://www.toptal.com/developers/gitignore/api/terraform

what is add.gitignore

The purpose of gitignore files is to ensure that certain files not tracked by git remain untracked.