shell中until的使用（ex27.sh）

最新推荐文章于 2022-04-29 17:03:42 发布

zhouyanldh

最新推荐文章于 2022-04-29 17:03:42 发布

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本文链接：https://blog.youkuaiyun.com/zhouyanldh/article/details/8123776

本文展示了bash脚本中使用until循环结构的基本用法，并通过实例演示了如何设置退出条件。包括循环测试、变量操作及最终退出流程。

#!/bin/bash

END_CONDITION=end

until [ "$var1" = "$END_CONDITION" ]
# Tests condition here, at top of loop.
do
  echo "Input variable #1 "
  echo "($END_CONDITION to exit)"
  read var1
  echo "variable #1 = $var1"
  echo
done  

# ------------------------------------------- #

#  As with "for" and "while" loops,
#+ an "until" loop permits C-like test constructs.

LIMIT=10
var=0

until (( var > LIMIT ))
do  # ^^ ^     ^     ^^   No brackets, no $ prefixing variables.
  echo -n "$var "
  (( var++ ))
done    # 0 1 2 3 4 5 6 7 8 9 10 


exit 0

[root@localhost shell]# ./ex27.sh
Input variable #1
(end to exit)
aa
variable #1 = aa

Input variable #1
(end to exit)
bbb
variable #1 = bbb

Input variable #1
(end to exit)
end
variable #1 = end

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