您熟悉bash的语法吗？"You're afraid of bugs? Get a bug!" --Joey Tribbiani, "FRIENDS".
想找个mini shell来看看源码，浏览了些网页，有“这玩意也配叫shell?”之感。
- bash-1.14.7.tar.gz 1996-08-29 1.4M
- bash-2.0.tar.gz 1996-12-31 1.3M gcc 12 编译不过。
- bash-3.0.tar.gz 2004-08-03 2.3M gcc 12 编译通过。
Debian 12用的是5.2.15 2022-12-13，最新的是5.3 2025-07-30 11M
搜bash-3.0.tar.gz，国内有镜像，下载速度很快。
When running configure, the script hangs for about 60 seconds on checking for mktime, eventually fails and moves on.
https://bugs.launchpad.net/adeona/+bug/407735
里面有个parse.y，看懂后自然就明白bash的语法啦！
源码里好像带了y.tab.c，没有yacc能也编译出bash。想修改parse.y再编译，需要apt install yacc.
贴部分代码：
%union {WORD_DESC *word; /* the word that we read. */int number; /* the number that we read. */WORD_LIST *word_list;COMMAND *command;REDIRECT *redirect;ELEMENT element;PATTERN_LIST *pattern;
}%start inputunitinputunit: simple_list simple_list_terminator| error '\n'| yacc_EOF;redirection: '>' WORD | '<' WORD | NUMBER '>' WORD ..simple_command_element: WORDshell_command: for_command| case_command| WHILE compound_list DO compound_list DONE| UNTIL compound_list DO compound_list DONE| select_command| if_command| subshell| group_command| arith_command| cond_command| arith_for_command;for_command: FOR WORD newline_list DO compound_list DONE| FOR WORD newline_list '{' compound_list '}'| FOR WORD ';' newline_list DO compound_list DONE| FOR WORD ';' newline_list '{' compound_list '}'| FOR WORD newline_list IN word_list list_terminator newline_list DO compound_list DONE| FOR WORD newline_list IN word_list list_terminator newline_list '{' compound_list '}'| FOR WORD newline_list IN list_terminator newline_list DO compound_list DONE| FOR WORD newline_list IN list_terminator newline_list DO compound_list DONE| FOR WORD newline_list IN list_terminator newline_list '{' compound_list '}';arith_for_command: FOR ARITH_FOR_EXPRS list_terminator newline_list DO compound_list DONE...if_command: IF compound_list THEN compound_list FI| IF compound_list THEN compound_list ELSE compound_list FI| IF compound_list THEN compound_list elif_clause FI;
我说过for i in 1 2 3; do echo $i; done和ls; ls; ls类似，这个说法很可能是错误的，因为AI说：
- YACC（Yet Another Compiler Compiler）由Stephen C. Johnson于1975年开发
- Bourne Shell（sh）由Stephen Bourne开发，于1979年末随UNIX第7版首次发布
所以sh一开始就用了YACC? 不对，没有sh前，cc yacc.c咋输入？第一个sh是汇编写的吧？
Bourne的音标是/bɔːrn/，电影《谍影重重》男主角的英文名为Jason Bourne（杰森·伯恩）。
parse.y, 不是parser.y, 也不是parsing.y. 虽然我昨天刚踩坑把n用了两次，可下面的程序还是有点过了吧：
function setupTextAreaLineSelection(textAreaId) {const textArea = document.getElementById(textAreaId);textArea.addEventListener('dblclick', function() {const start = this.selectionStart;const end = this.selectionEnd;let lineStart = start;let lineEnd = end;
dblclick，不是doubleClick啊。