Bash scripts I secretly use when I work on Rails apps. Presented last September 21, 2017 at the Philippine Ruby Users Group.

1. phackers.slack.com

5. Rails Scripts
by Marc Ignacio

7. Building Blocks

8. Building Blocks
• ps - process status
• bash pipes (|)
• grep & awk
• xargs

9. kill_spring

10. kill_spring
$ ps aux | grep spring
hawk 15572 0.0 0.2 2473876 17968 s002 S
6:36PM 0:00.31 spring server | sample-cms-app | started 13
secs ago
hawk 15339 0.0 0.2 2458516 17604 s002 S
6:35PM 0:00.41 spring server | userapp | started 50 secs ago
hawk 15701 0.0 0.0 2432804 1848 s002 R+
6:36PM 0:00.00 grep --color=auto spring

11. kill_spring
$ ps aux | grep spring | grep -v grep
hawk 15572 0.0 0.2 2473876 17968 s002 S
6:36PM 0:00.31 spring server | sample-cms-app | started
13 secs ago
hawk 15339 0.0 0.2 2458516 17604 s002 S
6:35PM 0:00.41 spring server | userapp | started 50 secs
ago

12. kill_spring
$ ps aux | grep spring | grep -v grep | awk '{print $2}'
15572
15339

13. kill_spring
$ ps aux | grep spring | grep -v grep | awk '{print $2}’ | xargs kill
# processes with PID 15572, 15339 are killed

14. kill_spring
$ alias kill_spring =
“ps aux | grep spring | grep -v grep | awk '{print $2}’ | xargs kill”

16. Don’t hoard
information

21. renice-rails

22. renice-rails
• nice
• CPU prioritisation [-20, 20]
• defaults to 0 or 10 (macOS)
• renice
• make a process more “nice”
• less “nice” - use sudo

23. renice-rails
#!/usr/bin/env sh
ps aux |
grep -E ‘rb-fsevent’ | grep -v grep | awk '{print $2}' |
tr 'n' ' ' |
xargs renice +15 -p

24. rubocop on git
pre-commit hook

26. .git/hooks/pre-commit
#!/usr/bin/env sh
if command -v rubocop > /dev/null; then
git status --porcelain
| grep -E '^A|^M'
| grep '.rb'
| awk '{print $2}'
| xargs rubocop
fi

28. .git/hooks/pre-commit
#!/usr/bin/env sh
if command -v rubocop > /dev/null; then
git status --porcelain
| grep -E '^A|^M'
| grep '.rb'
| awk '{print $2}'
| xargs rubocop
fi

29. Building Blocks
• ps - process status
• bash pipes (|)
• grep & awk
• xargs

30. Rails Scripts
• kill_spring
• renice-rails
• .git/hooks/pre-commit (rubocop)

31. Thanks!