chef best practice recommends to always replace the whole file, unfortunately this isn't always practical
bash "some_commands" do
user "root"
cwd "/tmp"
code <<-EOT
echo "alias rm='rm -i'" >> /root/.bashrc
EOT
end
cookbook_file "/root/.pip/pip.conf" do
source "pip.conf"
mode 0755
owner "root"
group "root"
end
bash "append_to_config" do
user "root"
code <<-EOF
cat /tmp/parms_to_append.conf >> /etc/config
rm /tmp/parms_to_append.conf
EOF
not_if "grep -q MY_IDENTIFIER /etc/config"
end