bash 从列剪切到行尾
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Cut from column to end of line
提问by KyleCrowley
I'm having a bit of an issue cutting the output up from egrep. I have output like:
我在切断 egrep 的输出时遇到了一些问题。我有这样的输出：
From: First Last
From: First Last
From: First Last
I want to cut out the "From: " (essentially leaving the "First Last").
我想删除“发件人：”（基本上留下“第一个”）。
I tried
我试过
cut -d ":" -f 7
but the output is just a bunch of blank lines.
但输出只是一堆空行。
I would appreciate any help.
我将不胜感激任何帮助。
Here's the full code that I am trying to use if it helps:
如果有帮助，这是我尝试使用的完整代码：
egrep '^From:' $file | cut -d ":" -f 7
NOTE: I've already tested the egrep portion of the code and it works as expected.
注意：我已经测试了代码的 egrep 部分，它按预期工作。
回答by Aaron Miller
The cutcommand lines in your question specify colon-separated fields and that you want the output to consist only of field 7; since there is no 7th field in your input, the result you're getting isn't what you intend.
cut您问题中的命令行指定以冒号分隔的字段，并且您希望输出仅包含字段 7；由于您的输入中没有第 7 个字段，因此您得到的结果不是您想要的。
Since the "From:" prefix appears to be identical across all lines, you can simply cut from the 7th character onward:
由于“From:”前缀在所有行中似乎都相同，您可以简单地从第 7 个字符开始：
egrep '^From:' $file | cut -c7-
and get the result you intend.
并得到你想要的结果。
回答by grim
The -fargument is for what fields. Since there is only one :in the line, there's only two fields. So changing -f 7to -f 2-will give you want you want. Albeit with a leading space.
该-f参数是哪些领域。由于:一行中只有一个，因此只有两个字段。所以改变-f 7到-f 2-会给你想要的。尽管有领先的空间。
回答by Alok--
You can combine the egrepand cutparts into one command with sed:
您可以将egrep和cut部分组合成一个命令sed：
sed -n 's/^From: //gp' $file
sed -nturns off printing by default, and then I am using pin the sedcommand explicitly to print the lines I want.
sed -n默认情况下关闭打印，然后我p在sed命令中明确使用来打印我想要的行。
回答by anubhava
You can use sed:
您可以使用 sed：
sed 's/^From: *//'
OR awk:
或 awk：
awk -F ': *' '=="From"{print }'
OR grep -oP
或者 grep -oP
grep -oP '^From: *\K.*'
回答by Johan Alexis Duque Cadena
you were really close.
你真的很亲近。
I think you only need to replace ":" with " " as separator and add "-" after the "7": like this:
我认为您只需要将“：”替换为“”作为分隔符并在“7”后添加“-”：像这样：
cut -d " " -f 2-
I tested and works pretty well.
我测试过，效果很好。
回答by Akhil Maskery
cutitself is a very handy tool in bash
cut本身是 bash 中一个非常方便的工具
cut -d (delimiter character) -f (fields that you want as output)
cut -d（分隔符）-f（您想要作为输出的字段）
a single field is given directly as -f 3 , range of fields can be selected as -f 5-9
单个字段直接指定为 -f 3 ，字段范围可以选择为 -f 5-9
so in your this particular case code would be
所以在你这个特殊情况下，代码将是
egrep '^From:' $file | cut -d\ -f 2-3
egrep '^From:' $file | 剪切 -d\ -f 2-3
the delimiter is space here and can be escaped using a \
分隔符在这里是空格，可以使用\进行转义
-f 1 corresponds to " From " and 2-3 corresponds to " First Last "
-f 1 对应“From”，2-3 对应“First Last”
回答by kenorb
Here is a Bash one-liner:
这是一个 Bash one-liner：
grep ^From file.txt | while read -a cols; do echo ${cols[@]:1}; done
See: Handling positional parametersat wiki.bash-hackers.org
请参阅：在 wiki.bash-hackers.org处理位置参数
