我有一部分bash脚本正在获得一个文件名,而不是扩展名,但是我正在想知道这里真正发生了什么.什么是“%%”？有人可以详细说明bash在幕后做什么吗？这种技术如何在一般的基础上使用？
#!/bin/bash
for src in *.tif
do
txt=${src%%.*}
tesseract ${src} ${txt}
done
解决方法
它删除文件扩展名(这里：.tif),示例：
$for A in test.py test.sh test.xml test.xsl; do echo "$A: ${A%%.*}"; done
test.py: test
test.sh: test
test.xml: test
test.xsl: test
从bash手册：
${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.
