[英]how awk print the regex it maps?
Here is the file contents:这是文件内容:
# cat text
16:10:29 DEBUG MY_Output:90 1 5de0d275c2f55: send response
As I do regex map with awk
:当我用
awk
做正则表达式映射时:
# cat text | awk '{if($0~/[0-9]{2}:[0-9]{2}:[0-9]{2}.*/) print $0}'
(print nothing)
# cat text | awk '/[0-9]{2}:[0-9]{2}:[0-9]{2}.*/ {print $0}'
(print nothing)
# cat text | awk '/[0-9]{2}:[0-9]{2}:[0-9]{2}.*/1'
16:10:29 DEBUG MY_Output:90 1 5de0d275c2f55: send response
My Question is: why {if($0~/[0-9]{2}:[0-9]{2}:[0-9]{2}.*/) print $0}
, /[0-9]{2}:[0-9]{2}:[0-9]{2}.*/ {print $0}
print nothing, but /[0-9]{2}:[0-9]{2}:[0-9]{2}.*/1
print the result.我的问题是:为什么
{if($0~/[0-9]{2}:[0-9]{2}:[0-9]{2}.*/) print $0}
, /[0-9]{2}:[0-9]{2}:[0-9]{2}.*/ {print $0}
什么都不打印,但是/[0-9]{2}:[0-9]{2}:[0-9]{2}.*/1
打印结果。
As I expected, the three expressions play the same meaning, as [1] describes, 1
, {print}
, {print $0}
do the same thing in action.正如我所料,这三个表达式具有相同的含义,正如[1]所描述的那样,
1
、 {print}
、 {print $0}
执行相同的操作。
Also the another experiment likely to check:还有另一个可能检查的实验:
# awk '{if(/[0-9]{2}:[0-9]{2}:[0-9]{2}/) print $0}' <<< "16:10:29"
(print nothing)
# awk '/[0-9]{2}:[0-9]{2}:[0-9]{2}/{print $0}' <<< "16:10:29"
(print nothing)
# awk '/[0-9]{2}:[0-9]{2}:[0-9]{2}/1' <<< "16:10:29"
16:10:29
Thank you very much.非常感谢。
After knowing OP's awk
version(in comments section) looks like it it OLD one so [0-9]{2}
is NOT supported in it(I believe so), so can you try following command once.在知道 OP 的
awk
版本(在评论部分)之后,它看起来像是旧版本,所以它不支持[0-9]{2}
(我相信是这样),所以你可以尝试一次以下命令。
awk '/[0-9][0-9]:[0-9][0-9]:[0-9][0-9]/' Input_file
This should work with your provided awk
version.这应该适用于您提供的
awk
版本。
Also with old version of awk
you could use --re-interval
to get it worked, I don't have that version with me so couldn't test it.此外,对于旧版本的
awk
您可以使用--re-interval
使其工作,我没有那个版本,因此无法对其进行测试。
awk --re-interval '/[0-9]{2}:[0-9]{2}:[0-9]{2}/' Input_file
In older versions of awk
to invoke EREs we need to include --re-interval
with awk
codes, hence it is NOT working with normal awk
code.在旧版本的
awk
,我们需要在awk
代码中包含--re-interval
来调用 ERE,因此它--re-interval
用于普通的awk
代码。
NOTE: In new versions of gawk
s --re-interval
is depreciated since OP has old version of awk
so have mentioned it in solution.注意:在新版本的
gawk
--re-interval
已贬值,因为 OP 具有旧版本的awk
因此在解决方案中提到了它。 Adding cross site reference link https://unix.stackexchange.com/questions/354553/awk-repetition-n-is-not-working as per OP's comments too here.根据 OP 的评论,添加跨站点参考链接https://unix.stackexchange.com/questions/354553/awk-repetition-n-is-not-working 。
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