shell中for循环和set的使用（ex22a.sh）

最新推荐文章于 2025-06-19 09:13:12 发布

zhouyanldh

最新推荐文章于 2025-06-19 09:13:12 发布

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本文链接：https://blog.youkuaiyun.com/zhouyanldh/article/details/8123592

本文介绍了一个简单的Shell脚本，该脚本用于展示各行星距离太阳的大致距离。通过解析变量并设置位置参数，脚本能够输出一系列行星名称及其对应的平均距离。

#!/bin/bash
# Planets revisited.

# Associate the name of each planet with its distance from the sun.

for planet in "Mercury 36" "Venus 67" "Earth 93"  "Mars 142" "Jupiter 483"
do
  set -- $planet  #  Parses variable "planet"
                  #+ and sets positional parameters.
  #  The "--" prevents nasty surprises if $planet is null or
  #+ begins with a dash.

  #  May need to save original positional parameters,
  #+ since they get overwritten.
  #  One way of doing this is to use an array,
  #         original_params=("$@")

  echo "$1		$2,000,000 miles from the sun"
  #-------two  tabs---concatenate zeroes onto parameter $2
done

# (Thanks, S.C., for additional clarification.)

exit 0

[root@localhost shell]# ./ex22a.sh

Mercury       36,000,000 miles from the sun
Venus       67,000,000 miles from the sun
Earth       93,000,000 miles from the sun
Mars       142,000,000 miles from the sun
Jupiter       483,000,000 miles from the sun