2019-11-24 feel too complicated, I just need to make link in
~/.profile already add it to
relogin 是真××烦，本身浪费时间不说，打开的应用全部都得关闭，尤其是我打开了倒计时的时候真想砸键盘，有什么资格笑话 Windows
The most common case where I need custom settting is Bash Terminal
If you really need a unified interface is every place (R
system(), Python subprocess, MATE top bar add application, …)
source ~/.local/bash/shell/profilerc.sh; # user defined alias source ~/.local/bash/shell/alias.sh # auxiliary function source ~/.local/bash/shell/function.sh
模仿 C++ micro to avoid source twice
For everyone using Linux (maybe someone using Windows as well), though he may not feel for environment variables, he is possibly very familiar with
PATH, and usually struggle with it for a hard time.
PATH is very important, but its meaning is very sophisticated. This contributes a lot to the steep learining curve of Linux, since you have to understand a very obscure concept at the very beginning 1.
It is very common to spend a long time in thoroughly understanding
PATH. I spent about a year (since I first used it) or more than a year and a half (since I first contacted it).
Let’s cut the cackle. On Ubuntu, there are two files, three classificaions. So the situation is far more complicated than bash的四种模式, and I simplify it to two most command cases.
2 two files
code block A # if running bash if [ -n "$BASH_VERSION" ]; then # include .bashrc if it exists if [ -f "$HOME/.bashrc" ]; then . "$HOME/.bashrc" fi fi code block B
code block C # If not running interactively, don't do anything case $- in ) ;; *i*) return;; *esac code block D
3 three classificaion
3.1 login and nologin shell
login shell uses
ssh, tty, desktop itself (including application from MATE panel, such as RStudio’s rsession)
nologin shell uses
ssh command, terminal (emulator)
3.2 Bash or not
~/.profile is sourced,
- Bash shell: A,
- other shell 2: A, B
3.3 interactive or non-interative
~/.bashrc is sourced,
- interactive shell: C, D
- non-interactive shell: C
4 two most command cases
The two most common cases are (1) terminal from desktop and (2) login via ssh or tty. It seems that they both include all the
PATH specification in both files, but the underlying mechanisms are quite different.
terminal from desktop
First, the desktop is a login, non-Bash shell; then terminal is a non-login, interactive shell, the result is A, B, C, D
login via ssh or tty
Instead, ssh or tty is a login, interactive, Bash shell, the result is A, C, D, B.
What I can’t imagine is the result of ssh command on remote machine and local machine is different. In theory, it should be C. But on local machine, the result is actually, A, B, C. It seems the path in desktop (via
~/.profile) is mixed into the ssh command in a unknown way 3.
6 finally solution
Don’t use this method if you don’t understand what I talked above, or you would easily run into trouble and don’t know how to solve it.
I make a file 4
#!/bin/bash # set the environment variable path # only run following block once if [ -z "$path" ]; then export path=yes # PATH specification here export PATH="$HOME/.local/bin:$HOME/.local/exec:$PATH" fi
and source it in both B part of
~/.profile and C part of
I’m still not successful with alias, https://stackoverflow.com/questions/30305973 may help.
Maybe I now know, unlike environment virables, function can’t be nested sourced. But I don’t want to maintain two file lists for now.