本文介绍了使用此bash的文件名萃取技术?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个是得到一个文件名没有扩展名bash脚本的一部分,但我想知道究竟怎么回事就在这里。什么是%%的呢?谁能细说什么bash的是做幕后?如何解决这个技术来一般的基础上使用?
#!/斌/庆典在* .TIF SRC
做
TXT = $ {SRC %%。*}
的tesseract $ {SRC} $ {} TXT
DONE
解决方案
它摆脱了文件的扩展名(这里的的.tif
) ,样本:
$对于A在test.py test.sh的test.xml test.xsl;做回声$ A:$ {A %%。*}; DONE
test.py:测试
test.sh:测试
的test.xml:测试
test.xsl:测试
从bash的手册:
$ {参数%%词}
word被扩展为一个模式,就像路径扩展。如果
模式参数扩展后的值的尾部相匹配,那么,
扩张的结果是参数的最短扩展值
匹配(``%''的情况)或者最长的匹配(``%%''
情况)删除。如果参数是@或*,模式删除应用
要依次在每个位置参数,最后扩展为结果的列表。
如果参数是@或*,模式删除下标数组变量
操作应用于反过来阵列的每个成员,并且膨胀是
结果的列表。
I have a portion of a bash script that is getting a filename without extension, but I'm trying to understand what is really going on here. What are the "%%"'s for? Can someone elaborate on what bash is doing behind the scenes? How can this technique be used on a general basis?
#!/bin/bash
for src in *.tif
do
txt=${src%%.*}
tesseract ${src} ${txt}
done
解决方案
It gets rid of the filename extension (here: .tif
), sample:
$ for A in test.py test.sh test.xml test.xsl; do echo "$A: ${A%%.*}"; done
test.py: test
test.sh: test
test.xml: test
test.xsl: test
from bash manual:
${parameter%%word}
The word is expanded to produce a pattern just as in pathname expansion. If the
pattern matches a trailing portion of the expanded value of parameter, then the
result of the expansion is the expanded value of parameter with the shortest
matching pattern (the ``%'' case) or the longest matching pattern (the ``%%''
case) deleted. If parameter is @ or *, the pattern removal operation is applied
to each positional parameter in turn, and the expansion is the resultant list.
If parameter is an array variable subscripted with @ or *, the pattern removal
operation is applied to each member of the array in turn, and the expansion is
the resultant list.
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