if语句条件内的while循环 Else语句内的While循环 while循环内的Try块 带有if语句的Bash while循环停滞在true循环中 Bash比较字符串在while循环中不起作用 while循环在附加的文件bash中中断到早期 在具有多个条件的bash中编写do while循环 " bash :未找到命令“使用while循环在bash中执行算术运算 在循环内字符串的起始...
二 使用举例 select 表达式是 bash 的一种扩展应用，擅长于交互式bool 是表示 true 或 false 的基础数...
Single quotes in bash will suppress special meaning of every meta characters. Therefore meta characters will be read literally. It is not possible to use another single quote within two single quotes not even if the single quote is escaped by backslash. #!/bin/bash #Declare bash string variab...
The statements[ -z "$X" ]andecho "The environment variable X is not set."andusageare used to test if the string is null (-z) and if so, then perform the echo statement saying that it is not set and invoke the "usage" function discussed below. If your script does not use flags,...
Basic If statements A basic if statement commands that if a particular condition is true, then only execute a given set of actions. If it is not true, then do not execute those actions. If statement is based on the following format: ...
If statement in Bash We can also implementifstatements for additional functions. #!/bin/bash echo “Who is there?” read name if [ $name ] echo “Hello $name” else echo “Must’ve been my imagination” fi In the terminal: ~$bash name.sh ...
-ge 大于等于,如:if [ "a"−ge"b" ] -lt 小于,如:if [ "a"−lt"b" ] -le 小于等于,如:if [ "a"−le"b" ] < 小于(需要双括号),如:(("a"<"b")) <= 小于等于(需要双括号),如:(("a"<="b")) > 大于(需要双括号),如:(("a">"b")) ...
. # The return statement terminates the function. # You can think of it as the function’s exit status. return 55}# assigning to the func_result variable using the $() mechanismfunc_result=$(greeting 'Joe')# console: return:55echo "return:$?"# console: func_result:Hello Joe...
@draemon,set -e对可移植性(不仅跨shell,而且跨shell中的各个版本)、可预测性以及非平凡代码的可读性都是非常有害的。我很乐意为任何不建议使用它的决定辩护。参见ulm.de/~mascheck/variable/set-e,专门关注与可移植性相关的行为方面。 @Charlesduffy,in the case where trap calls EDOCX1 original 0 command....
The previous Bash “for” loop will run. When “file2” is met, it will break. The following image displays how the loop will execute. Note how the other files are not echoed since the condition in the “if” statement is met.