Linux 使用“|”进行搜索 替代运算符
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grepping using the "|" alternative operator
提问by MattLBeck
The following is a sample of a large file named AT5G60410.gff:
以下是一个名为 AT5G60410.gff 的大文件示例：
Chr5 TAIR10 gene 24294890 24301147 . + . ID=AT5G60410;Note=protein_coding_gene;Name=AT5G60410
Chr5 TAIR10 mRNA 24294890 24301147 . + . ID=AT5G60410.1;Parent=AT5G60410;Name=AT5G60410.1;Index=1
Chr5 TAIR10 protein 24295226 24300671 . + . ID=AT5G60410.1-Protein;Name=AT5G60410.1;Derives_from=AT5G60410.1
Chr5 TAIR10 exon 24294890 24295035 . + . Parent=AT5G60410.1
Chr5 TAIR10 five_prime_UTR 24294890 24295035 . + . Parent=AT5G60410.1
Chr5 TAIR10 exon 24295134 24295249 . + . Parent=AT5G60410.1
Chr5 TAIR10 five_prime_UTR 24295134 24295225 . + . Parent=AT5G60410.1
Chr5 TAIR10 CDS 24295226 24295249 . + 0 Parent=AT5G60410.1,AT5G60410.1-Protein;
Chr5 TAIR10 exon 24295518 24295598 . + . Parent=AT5G60410.1
I am having some trouble extracting specific lines from this using grep. I wanted to extract all lines that are of type "gene" or type "exon", specified in the third column. I was suprised when this did not work:
我在使用 grep 从中提取特定行时遇到了一些麻烦。我想提取第三列中指定的“基因”类型或“外显子”类型的所有行。当这不起作用时，我感到很惊讶：
grep 'gene|exon' AT5G60410.gff
No results are returned. Where have I gone wrong?
不返回任何结果。我哪里错了？
采纳答案by Jeff Foster
You need to escape the |. The following should do the job.
你需要逃离|. 以下应该完成这项工作。
grep "gene\|exon" AT5G60410.gff
回答by a'r
By default, grep treats the typical special characters as normal characters unless they are escaped. So you could use the following:
默认情况下，grep 将典型的特殊字符视为普通字符，除非它们被转义。所以你可以使用以下内容：
grep 'gene\|exon' AT5G60410.gff
However, you can change its mode by using the following forms to do what you are expecting:
但是，您可以通过使用以下表单来更改其模式以执行您期望的操作：
egrep 'gene|exon' AT5G60410.gff
grep -E 'gene|exon' AT5G60410.gff
回答by Nathan Fellman
This is a different way of grepping for a few choices:
这是对几个选择进行搜索的不同方式：
grep -e gene -e exon AT5G60410.gff
the -eswitch specifies different patterns to match.
该-e开关指定不同的图案相匹配。
回答by ennuikiller
This will work:
这将起作用：
grep "gene\|exon" AT5G60410.gff
回答by entpnerd
I found this question while googling for a particular problem I was having involving a piped commandto a grepcommand that used the alternation operator in a regex, so I thought that I would contribute my more specialized answer.
我在谷歌搜索一个特定问题时发现了这个问题，我涉及一个管道命令到一个grep在正则表达式中使用交替运算符的命令，所以我想我会贡献我更专业的答案。
The error I faced turned out to be with the previous pipe operator (i.e. |) and not the alternation operator (i.e. |identical to pipe operator) in the grep regex at all. The answer for me was to properly escape and quote as necessary special shell characters such as &before assuming the issue was with my grep regex that involved the alternation operator.
我遇到的错误原来是与之前的管道操作符（即|），而不是|grep 正则表达式中的交替操作符（即与管道操作符相同）。对我来说，答案是在假设问题出在我的 grep 正则表达式中涉及交替运算符之前，正确地转义并引用必要的特殊 shell 字符，例如 &。
For example, the command I executed on my local machine was:
例如，我在本地机器上执行的命令是：
get http://localhost/foobar-& | grep "fizz\|buzz"
This command resulted in the following error:
此命令导致以下错误：
-bash: syntax error near unexpected token `|'
This error was corrected by changing my command to:
通过将我的命令更改为：
get "http://localhost/foobar-&" | grep "fizz\|buzz"
By escaping the &character with double quotes I was able to resolve my issue. The answer had nothing to do with the alternation operation at all.
通过&用双引号转义字符，我能够解决我的问题。答案与交替操作完全无关。
