bash 在数组上使用 GREP 来查找单词
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Use GREP on array to find words
提问by Computernerd
Given the following array in Shell Programming
给定以下 Shell 编程中的数组
foo=(spi spid spider spiderman bar lospia)
foo=(spi spid 蜘蛛蜘蛛侠酒吧 lospia)
I would like to use GREP to search for all words in the array which has the 3 letters spi
我想使用 GREP 搜索数组中包含 3 个字母的所有单词 spi
Correct output : spi spi spider spiderman lospia
正确输出：spi spi蜘蛛蜘蛛侠lospia
I have tried something like this
我试过这样的事情
foo=(spi spid spider spiderman)
grep "spi" foo
But it seems it is wrong , what is the correct way to go about it ???
但它似乎是错误的，正确的做法是什么？？？
采纳答案by CrazyCasta
The following will print out all words that contain spi:
以下将打印出所有包含 spi 的单词：
foo=(spi spid spider spiderman bar)
for i in ${foo[*]}
do
echo $i | grep "spi"
done
回答by mockinterface
The simplest solution would be to pipe the array elements into grep:
最简单的解决方案是将数组元素通过管道传输到 grep 中：
printf -- '%s\n' "${foo[@]}" | grep spi
A couple of notes:
一些注意事项：
printfis a bash builtin, and you can look it up with man printf. The --option tells printf that whatever follows is not a command line option. That guards you from having strings in the fooarray being interpreted as such.
printf是一个内置的 bash，你可以用man printf. 该--选项告诉 printf 后面的内容不是命令行选项。这可以防止您将foo数组中的字符串解释为这样。
The notation of "${foo[@]}"expands all the elements of the array as standalone arguments. Overall the words in the array are put into a multi-line string and are piped into grep, which matches every individual line against spi.
的符号"${foo[@]}"将数组的所有元素扩展为独立参数。总的来说，数组中的单词被放入一个多行字符串中，并通过管道传送到 grep，它与spi匹配每一行。
回答by John1024
IFS=$'\n' ; echo "${foo[*]}" | grep spi
This produces the output:
这会产生输出：
spi
spid
spider
spiderman
lospia
回答by David Pointon
If the requirement is to run the script/extract under the exit-on-error shell flag ('-e') and unnecessarily exiting the script/extract whilst also avoiding the tedium of wrapping the code in "set +e" … "set -e", I always use case since unlike grep(1) or test(1), it (case) doesn't update $? …
如果要求是在出错时退出 shell 标志 ('-e') 下运行脚本/提取并不必要地退出脚本/提取，同时还避免将代码包装在“set +e”中的乏味……“set -e"，我总是使用 case，因为与 grep(1) 或 test(1) 不同，它 (case) 不更新 $? …
for e in "${foo[@]}" ; do
case "$f" in
*spi*) echo $f ;;
esac
done
