Add bash profile startup time profiling capability

[oinume]

Summary

Added an optional profiling system to .bash_profile that measures and logs the startup time of different initialization sections. This helps identify performance bottlenecks during shell startup.

BASH_PROFILE_PROFILING=1

Key Changes

• Profiling Framework: Added a conditional profiling system that can be enabled via BASH_PROFILE_PROFILING=1 bash -l
• Time Measurement: Implemented _bp_get_ms() function with fallback support for:
  • EPOCHREALTIME (preferred, highest precision)
  • gdate (GNU date, fallback for macOS)
  • Standard date command (lowest precision fallback)
• Logging Function: Added _bp_log() that prints cumulative time since profile start and delta time since last log point
• Instrumentation: Added _bp_log calls throughout the profile to measure initialization time of major sections:
  • Prompt/history setup
  • Homebrew initialization
  • Bash completion
  • Bash-it framework
  • FZF configuration
  • Bash-powerline
  • Tmuxinator
  • Git completion
  • Language runtime managers (rbenv, JDK, nvm, mise)
  • Other tools (direnv, wtp, pnpm, google-cloud-sdk)
• Cleanup: Profiling functions and variables are unset at the end when profiling is enabled
• Minor Fixes: Fixed trailing whitespace issues in existing code

Implementation Details

• Profiling is completely opt-in and has zero overhead when disabled
• Output is sent to stderr to avoid interfering with stdout
• Uses ANSI color codes (yellow) for visual distinction of profile output
• Provides both cumulative and incremental timing information for each section

result

BASH_PROFILE_PROFILING=1 bash -l
[profile]     15 ms (+  15 ms) prompt/history
[profile]     74 ms (+  59 ms) brew --prefix
[profile]     84 ms (+  10 ms) .bash_local
[profile]     96 ms (+  12 ms) bash-completion
[profile]    750 ms (+ 654 ms) bash-it
[profile]    796 ms (+  46 ms) fzf
[profile]    803 ms (+   7 ms) bash-powerline
[profile]    811 ms (+   8 ms) tmuxinator
[profile]    818 ms (+   7 ms) completion (git)
[profile]    833 ms (+  15 ms) google-cloud-sdk
[profile]    986 ms (+ 153 ms) rbenv
[profile]   1005 ms (+  19 ms) JDK (java_home)
[profile]   1489 ms (+ 484 ms) nvm
[profile]   1525 ms (+  36 ms) mise
[profile]   1544 ms (+  19 ms) wtp
[profile]   1560 ms (+  16 ms) direnv
[profile]   1566 ms (+   6 ms) nvm bash_completion
[profile]   1574 ms (+   8 ms) ===== TOTAL =====

https://claude.ai/code/session_01KUTPUqiighqZpzEWb3mdVK