Optimize ~/.bashrc.d/* loading time to make new terminals load faster

[jankeromnes]

I added a few date -Ins into a ~/.bashrc on Gitpod, and found that loading all $HOME/.bashrc.d/* scripts:

https://github.com/gitpod-io/workspace-images/blob/baa144a3292c13a17d56f38d7f67653edd59daf2/base/Dockerfile#L54

... can take 313ms (sample size = 1)

---

Adding a few more date -Ins showed me that the longest-running $HOME/.bashrc.d/* scripts could be:

https://github.com/gitpod-io/workspace-images/blob/baa144a3292c13a17d56f38d7f67653edd59daf2/full/Dockerfile#L158-L160

... 109ms (sample size = 1)

https://github.com/gitpod-io/workspace-images/blob/baa144a3292c13a17d56f38d7f67653edd59daf2/full/Dockerfile#L188

... 116ms (sample size = 1)

[axonasif]

~~Hi @jankeromnes! I could load everything in $HOME/.bashrc.d within just 0.001s with source $HOME/.bashrc.d/*. While this takes lot more cpu cycles and invocations of source command over the unnecessary for loop with ls, thus making it kinda slower~~ 😓

~~Here are some logs~~ 😄

gitpod /workspace/workspace-images $ time (for i in $(ls $HOME/.bashrc.d/*); do source $i; done)

real    0m0.197s
user    0m0.151s
sys     0m0.083s
gitpod /workspace/workspace-images $ time (source $HOME/.bashrc.d/*)
real    0m0.001s
user    0m0.000s
sys     0m0.001s
gitpod /workspace/workspace-images $ time (source $HOME/.bashrc.d/*)

real    0m0.001s
user    0m0.000s
sys     0m0.001s
gitpod /workspace/workspace-images $ time (for i in $(ls $HOME/.bashrc.d/*); do source $i; done)

real    0m0.239s
user    0m0.175s
sys     0m0.061s
gitpod /workspace/workspace-images $ time (for i in $(ls $HOME/.bashrc.d/*); do source $i; done)

real    0m0.209s
user    0m0.151s
sys     0m0.096s
gitpod /workspace/workspace-images $ 

Edit: Well nope, sorry, my bad. source only takes one filename at a time, missed that point.