bash命令`cd/usr/local/src`(包括反引号)无效 [英] bash command `cd /usr/local/src` (including backticks) has no effect

问题描述

我对bash还是很陌生，所以我不知道这个问题出现在哪里. 但是，我有这个脚本，应该只更改cd，下载tar文件并将其解压缩. 我正在从/home/

I am fairly new to bash, so I don't know where this problem is appearing. But, I have this script, which is supposed to just change cd, download a tar file and extract it. I am applying this command from /home/

#!/bin/bash
`cd /usr/local/src`
`wget http://nginx.org/download/nginx-1.6.2.tar.gz -O nginx-1.6.2.tar.gz`
`tar -xzf  nginx-1.6.2.tar.gz`

因此，此下载tar文件并提取到主目录中，而不是在/usr/local/src

So, this download the tar file and extracts in home, instead of in /usr/local/src

我已经阅读到cd命令可能存在问题，但是我不知道如何解决此问题.

I have read that this might be a problem from the cd command, but I don't know how to fix this.

推荐答案

编辑后，您的脚本现在显示您正在运行

As edited, your script now says that you're running

#!/bin/bash
`cd /usr/local/src`
`wget http://nginx.org/download/nginx-1.6.2.tar.gz -O nginx-1.6.2.tar.gz`
`tar -xzf  nginx-1.6.2.tar.gz`

反引号引起每个命令在子shell中运行；以及每个子shell的输出将被读取，字符串分割并作为第二个命令运行.

The backticks cause each command to be run in a subshell; and each subshell's output to be read, string-split, and run as a second command.

此外，由于cd位于子外壳中，因此其效果不会延续到主外壳中.

Also, because the cd is in a subshell, its effects don't carry over to the main shell.

因此:删除反引号(并确保您的脚本在cd失败的情况下退出；我在这里使用-e标志执行此操作).您应该只在运行:

So: Remove the backticks (and make sure your script exits if the cd fails; I do this here with the -e flag). You should only be running:

#!/bin/bash -e
cd /usr/local/src
wget http://nginx.org/download/nginx-1.6.2.tar.gz -O nginx-1.6.2.tar.gz
tar -xzf  nginx-1.6.2.tar.gz

...也就是说，您的命令不得以`字符开头和结尾.

...which is to say: Your commands must not start and end with ` characters.

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