#In your ~/.gitconfig you can put something like this.
# git version > 2.13
# https://stackoverflow.com/questions/8801729/is-it-possible-to-have-different-git-config-for-different-projects/43884702#43884702
[includeIf "gitdir:~/company_a/"]
  path = .gitconfig-company_a
[includeIf "gitdir:~/company_b/"]
  path = .gitconfig-company_b



#Example contents of .gitconfig-company_a

[user]
name = Pradeep singh
email = pradeep@companya.net

#Example contents of .gitconfig-company_b

[user]
name = Pradeep Singh
email = ps@companyb.com