cat <<-EOF
Hello, World
EOF

最后的「EOF」前面不能用空格缩进，tab 可以。:)

- https://en.wikipedia.org/wiki/Here_document#Unix_shells
- https://stackoverflow.com/a/18660985

#shell #til

#今天又看了啥 #shell
shell 登录到退出的调用关系
https://blog.flowblok.id.au/static/images/shell-startup-actual.png
https://blog.flowblok.id.au/2013-02/shell-startup-scripts.html

$HOME vs. ~ (tilde)
https://newbedev.com/difference-between-home-and-tilde

The tilde is part of a shell expansion (like in bash, csh, zsh, etc). The $HOME variable is exportable and can be used independent of a specific shell.

The shell replaces ~ with the user's home directory (update: or perhaps by the home directory of some other user, if ~ is followed by something other than a /), but only if it's the first character of a word.

#shell

source vs. . (dot)
https://ss64.com/bash/source.html

source is a synonym for dot/period '.' in bash, but not in POSIX sh, so for maximum compatibility use the period.

When a script is run using source it runs within the existing shell, any variables created or modified by the script will remain available after the script completes.

E.g. https://github.com/nvm-sh/nvm/blob/eed0d0e85ccb35e8802b0df7061491e6cf5d6a4b/README.md

#shell

eval is a built-in Linux command which is used to execute arguments as a shell command. It combines arguments into a single string and uses it as an input to the shell and execute the commands.

https://www.geeksforgeeks.org/eval-command-in-linux-with-examples/

#shell

我没有在 .zshrc 设定语言区域，而 ssh 配置默认发送环境变量 SendEnv LANG LC_*。虚拟终端 Terminal.app 和 iTerm.app 会设定环境变量 LC_CTYPE=UTF-8，这对 macOS 有效，但对 Linux 无效。这导致远程 Linux 主机 #shell 中的一些字符显示异常。

locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=
LANGUAGE=
LC_CTYPE=UTF-8
LC_NUMERIC="POSIX"
LC_TIME="POSIX"

抓取 (reparent) 一个运行中的程序到当前终端（一直想要这个功能……）：

echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
reptyr PID

via https://t.me/MiaoTonyChannel/2242
#shell