bash startup optimisation (5x faster)

[lbonvarl]

With a few minor tweaks, we are able to improve quite a bit the bash startup (from 80ms to 14ms on my old system HP6200 i7 2600)

See the diff below from v3.0.2 on ~/.local/share/omarchy/default/bash. This is mostly checking for interactive shells and delay completions until when it is actually used.

Note I still use day to day zsh (via chsh /usr/bin/zsh command along with the incredible https://github.com/romkatv/zsh4humans)

git diff
diff --git a/default/bash/init b/default/bash/init
index 149b16c..928f0a4 100644
--- a/default/bash/init
+++ b/default/bash/init
@@ -1,4 +1,9 @@
-if command -v mise &> /dev/null; then
+# Only for interactive shells
+if [[ $- != *i* ]]; then
+  return 0
+fi
+
+if command -v mise &>/dev/null; then
   eval "$(mise activate bash)"
 fi

@@ -10,11 +15,16 @@ if command -v zoxide &> /dev/null; then
   eval "$(zoxide init bash)"
 fi

-if command -v fzf &> /dev/null; then
-  if [[ -f /usr/share/fzf/completion.bash ]]; then
-    source /usr/share/fzf/completion.bash
-  fi
-  if [[ -f /usr/share/fzf/key-bindings.bash ]]; then
-    source /usr/share/fzf/key-bindings.bash
+# fzf: key-bindings now; completion lazy on first TAB
+if command -v fzf &>/dev/null; then
+  [[ -f /usr/share/fzf/key-bindings.bash ]] && source /usr/share/fzf/key-bindings.bash
+  if shopt -q progcomp 2>/dev/null && [[ -f /usr/share/fzf/completion.bash ]]; then
+    _lazy_fzf_comp() {
+      bind -r '"\t"' 2>/dev/null || true
+      source /usr/share/fzf/completion.bash
+      builtin bind '"\t":complete'
+      READLINE_LINE=$READLINE_LINE; READLINE_POINT=$READLINE_POINT
+    }
+    bind -x '"\t":_lazy_fzf_comp'
   fi
 fi
diff --git a/default/bash/prompt b/default/bash/prompt
index 4901a58..804b786 100644
--- a/default/bash/prompt
+++ b/default/bash/prompt
@@ -1,3 +1,11 @@
+# Prompt is only meaningful for interactive shells
+[[ $- == *i* ]] || return 0
+
+ # Technicolor dreams
+ force_color_prompt=yes
+ color_prompt=yes
+
+
 # Technicolor dreams
 force_color_prompt=yes
 color_prompt=yes
diff --git a/default/bash/shell b/default/bash/shell
index 7b39de7..e6dfc41 100644
--- a/default/bash/shell
+++ b/default/bash/shell
@@ -4,8 +4,10 @@ HISTCONTROL=ignoreboth
 HISTSIZE=32768
 HISTFILESIZE="${HISTSIZE}"

-# Autocompletion
-if [[ ! -v BASH_COMPLETION_VERSINFO && -f /usr/share/bash-completion/bash_completion ]]; then
+# Autocompletion (interactive only, and only if progcomp enabled)
+if [[ $- == *i* ]] && shopt -q progcomp 2>/dev/null \
+   && [[ ! -v BASH_COMPLETION_VERSINFO ]] \
+   && [[ -f /usr/share/bash-completion/bash_completion ]]; then
   source /usr/share/bash-completion/bash_completion
 fi