Show user@host when running in a container (#564)

pure.zsh

@@ -680,6 +680,9 @@ prompt_pure_state_setup() {
 	# Show `username@host` if logged in through SSH.
 	[[ -n $ssh_connection ]] && username='%F{$prompt_pure_colors[user]}%n%f'"$hostname"
 
+	# Show `username@host` if inside a container.
+	prompt_pure_is_inside_container && username='%F{$prompt_pure_colors[user]}%n%f'"$hostname"
+
 	# Show `username@host` if root, with username in default color.
 	[[ $UID -eq 0 ]] && username='%F{$prompt_pure_colors[user:root]}%n%f'"$hostname"
 
@@ -691,6 +694,12 @@ prompt_pure_state_setup() {
 	)
 }
 
+# Return true if executing inside a Docker or LXC container.
+prompt_pure_is_inside_container() {
+	([[ -r /proc/1/cgroup ]] && grep -q -E "(lxc|docker)" /proc/1/cgroup ) \
+		|| [[ "$container" == "lxc" ]]
+}
+
 prompt_pure_system_report() {
 	setopt localoptions noshwordsplit
 

readme.md

@@ -40,7 +40,7 @@ Most prompts are cluttered, ugly and slow. We wanted something visually pleasing
 - Indicates when you have unpushed/unpulled `git` commits with up/down arrows. *(Check is done asynchronously!)*
 - Prompt character turns red if the last command didn't exit with `0`.
 - Command execution time will be displayed if it exceeds the set threshold.
-- Username and host only displayed when in an SSH session.
+- Username and host only displayed when in an SSH session or a container.
 - Shows the current path in the title and the [current folder & command](screenshot-title-cmd.png) when a process is running.
 - Support VI-mode indication by reverse prompt symbol (Zsh 5.3+).
 - Makes an excellent starting point for your own custom prompt.