bash 用于将磁盘添加到 fstab（如果不存在）的脚本
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Script for adding a disk to fstab if not existing
提问by h0ch5tr4355
First of all, I have read many posts (see at bottom) with if-clauses to search in a file for a specific string and followed these posts 1to1, however I don't manage to get my script to work. I want to make an entry in /etc/fstabif it doesn't exist yet:
首先，我已经阅读了许多带有 if 子句的帖子（见底部）以在文件中搜索特定字符串并按照 1to1 的顺序关注这些帖子，但是我无法让我的脚本正常工作。/etc/fstab如果尚不存在，我想输入：
#!/bin/bash
fstab=/etc/fstab
if grep -q "poky-disc" "$fstab"
then
echo "#poky-disc" >> /etc/fstab
echo "/dev/sdb1 /media/poky ext4 defaults 0 2" >> /etc/fstab
else
echo "Entry in fstab exists."
fi
Thanks for your help in advance. These are the similar posts, which didnt help me further:
提前感谢您的帮助。这些是类似的帖子，并没有进一步帮助我：
回答by tripleee
Here's a simple and hopefully idiomatic solution.
这是一个简单且希望是惯用的解决方案。
grep -q 'init-poky' /etc/fstab ||
printf '# init-poky\n/dev/sdb1 /media/poky ext4 defaults 0 2\n' >> /etc/fstab
If the exit status from grep -qis false, execute the printf. The ||shorthand can be spelled out as
如果退出状态grep -q为false，则执行printf. 该||速记可以拼写为
if grep -q 'ínit-poky' /etc/fstab; then
: nothing
else
printf ...
fi
Many beginners do not realize that the argument to ifis a command whose exit status determines whether the thenbranch or the elsebranch will be taken.
很多初学者没有意识到，to 的参数if是一个命令，它的退出状态决定了是then分支还是else分支被采用。
回答by Arunas Bartisius
Elegant and short way:
优雅而简短的方式：
#!/bin/bash
if ! grep -q 'init-poky' /etc/fstab ; then
echo '# init-poky' >> /etc/fstab
echo '/dev/sdb1 /media/poky ext4 defaults 0 2' >> /etc/fstab
fi
It uses native Bash command exit code ($?=0 for success and >0 for error code) and if grep produces error, means NOT FOUND, it does inverse (!) of result, and adds fstab entry.
它使用本机 Bash 命令退出代码（$?=0 表示成功，>0 表示错误代码），如果 grep 产生错误，则意味着未找到，它会反转 (!) 结果，并添加 fstab 条目。
回答by Noy Tsarfaty
I had the same issue. I managed to edit it with this command:
我遇到过同样的问题。我设法用这个命令编辑它：
sudo su -c "echo '#test' >> /etc/fstab"
回答by kyokose
#!/bin/bash
fstab=/etc/fstab
if [[ $(grep -q "poky-disc" "$fstab") ]]
# forgiving me for being a bit of over-rigorous, you might want to change this matching word, as below, 'poky-disc' merely a comment, not exactly a config line, so
then
echo "#poky-disc" >> /etc/fstab
echo "/dev/sdb1 /media/poky ext4 defaults 0 2" >> /etc/fstab
else
echo "Entry in fstab exists."
fi
