第一种：单句 IF <布尔表达式> THEN PL/SQL 和 SQL语句 END IF; 第二种：二重复句 IF <布尔表...
if in THEN_BLOCK and if_result was SUCESS then yes * if in THEN_BLOCK and if_result was FAIL then no * if in WANT_THEN then syntax error(sh is different) */ { int rv = 1; if (if_state == WANT_THEN) { syn_err("then expected"); rv = 0; } else if (if_state == THEN...
bash,pdksh和tcsh分别都有两种不同形式的条件语句:if语句和case语句. (1)if语句 语法格式: bash/pdksh用法: if [expression1] then commands1 elif [expression2] commands2 else commands3 fi tcsh用法: if (expression1) then commands1 else if (expression2) then commands2 else commands3 endif 含义:当...
Since the first argument to this script was4, and 4 is equal to 4, the code within the IF statement was executed. You can pair IF statements with ELSE statements. An ELSE statement only runs if the conditional expression being evaluated by the IF statement is false. Let’s create a simp...
" If using a dark background within the editing area and syntax highlighting " turn on this option as well "set background=dark " Uncomment the following to have Vim jump to the last position when " reopening a file "if has("autocmd") ...
else if ("$foo" = "You lose") then echo $foo endif[注意,我们必须在发现foo没有被定义的时候'set foo'.] 清楚了么?错误码和错误检查我们上面的例子没有指出file命令如何将错误返回给脚本。事实上,它 根本就没有返回错误。错误被忽略了。这不是因为我们粗心大意:许多Unix shell脚本(以及其他程序)忽略所...
If, elif in Unix:Below is the syntax of If, Else if, Else condition in Unix….more… Advanced Unix Commands GREP command in Unix: This command is used to find the whether the search criteria is available in the file and if the search criteria matches then it will print the matching li...
url-highlighter - A plugin for the ZSH syntax highlighter that turns URLs green if they respond with a "good" status, and red otherwise. Useful for checking URL typos. uv-env - Automatically uses uv to activate a virtual environment based on the current directory. uvenv - Extends the funct...
语法分析(syntax parser) 语法分析就是将 token 列表中的元素作为表达式(expression)并以节点为单位构建语法树, 简单命令是一个表达式,而复合命令以及命令序列是多个表达式的组合。Thompson Shell 中以简单数组作为语法树的容器,实际上这是结构体的一种变形,只不过每个成员字段大小都一样(都是 sizeof int)而已。一个...
if(envvar) { printf("%s\n",envvar); } else { printf("not set.\n"); } 现在假设你想创建一个新的环境变量,变量名为‘MYVAR’,值为‘MYVAL’。 以下是你将怎样做: static char envbuf[256]; sprintf(envbuf,"MYVAR=%s","MYVAL");