- write an ls command that lists files in the following manner
题目详情
Read man ls and write an ls command that lists files in the following manner
- Includes all files, including hidden files
- Sizes are listed in human readable format (e.g. 454M instead of 454279954)
- Files are ordered by recency
- Output is colorized
A sample output would look like this
-rw-r--r-- 1 user group 1.1M Jan 14 09:53 baz
drwxr-xr-x 5 user group 160 Jan 14 09:53 .
-rw-r--r-- 1 user group 514 Jan 14 06:42 bar
-rw-r--r-- 1 user group 106M Jan 13 12:12 foo
drwx------+ 47 user group 1.5K Jan 12 18:08 ..翻译
阅读 man ls 并且让ls命令按照如下条件输出
- 包括所有文件，包括隐藏文件
- 文件大小转换成好理解的格式 比如 454M 而不是 454279954
- 文件按照最近修改的日期排序
- 输出有颜色
下面是示例
-rw-r--r-- 1 user group 1.1M Jan 14 09:53 baz
drwxr-xr-x 5 user group 160 Jan 14 09:53 .
-rw-r--r-- 1 user group 514 Jan 14 06:42 bar
-rw-r--r-- 1 user group 106M Jan 13 12:12 foo
drwx------+ 47 user group 1.5K Jan 12 18:08 ..解答
- 显示所有文件
~ » ls -a - 文件大小格式
~ » ls -lh 130 ↵ sky@sky-virtual-machine
total 52K
drwxr-xr-x 11 sky sky 4.0K 5月 24 08:35 Desktop
drwxr-xr-x 2 sky sky 4.0K 5月 13 23:04 Documents
- 文件顺序
~ » ls -lt sky@sky-virtual-machine
total 52
drwxr-xr-x 11 sky sky 4096 5月 24 08:35 Desktop
-rw-rw-r-- 1 sky sky 6 5月 22 14:00 hello.txt
drwxr-xr-x 5 sky sky 4096 5月 20 10:31 Downloads
- 输出有颜色
# 我这个本身就有颜色的- write bash functions marco and polo that do the following
题目详情
write bash functions marco and polo that do the following. Whenever you execute marco the current working directory should be saved in some manner, then when you execute polo, no matter what directory you are in, polo should cd you back to the directory where you executed marco. For ease of debugging you can write the code in a file marco.sh and (re)load the definitions to your shell by executing source marco.sh.
翻译
写两个bash函数功能如下。当你运行marco，当前的工作目录会用某种方式保存，之后当你运行polo的时候，不论你当前在哪个目录，polo会cd回到运行marco的目录。为了方便debug你可以将代码写进marco.sh并且通过source marco.sh加载这个命令.
解答
marco脚本中要保留pwd命令的值 polo脚本要cd到marco脚本保留到的变量中去
marco.sh
#!/bin/bash
dir=$(pwd)
echo $dirpolo.sh
#!/bin/bash
cd $dir
- say you have a command that fails rarely
题目详情
Say you have a command that fails rarely. In order to debug it you need to capture its output but it can be time consuming to get a failure run. Write a bash script that runs the following script until it fails and captures its standard output and error streams to files and prints everything at the end. Bonus points if you can also report how many runs it took for the script to fail. 脚本如下
#!/usr/bin/env bash
n=$(( RANDOM % 100 ))
if [[ n -eq 42 ]]; then
echo "Something went wrong"
>&2 echo "The error was using magic numbers"
exit 1
fi
echo "Everything went according to plan"翻译
你有一个经常失败的命令。为了debug你需要获得这个脚本的输出，但是这个脚本发生错误的时间不固定。你需要写一个bash脚本来监控这个脚本直到这个脚本运行错误了，并且把脚本输出和错误重定向到文件中。附加功能是能记录这个脚本跑了多少次才失败
解答
#!/bin/bash
cnt=1
while true
do
source wrong.sh > error.log 2>&1
if [ $? -eq 1 ]
then
break
else
echo "the shell runs good"
fi
echo "run $cnt times"
cnt=$[$cnt + 1]
done