bash 文件名开始匹配
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bash filename start matching
提问by Display
I've got a simple enough question, but no guidance yetthrough the forums or bash. The question is as follows:
我有一个足够简单的问题，但还没有通过论坛或 bash 获得指导。问题如下：
I want to add a prefix string to each filename in a directory that matches *.h or *.cpp. HOWEVER, if the prefix has already been applied to the filename, do NOT apply it again.
我想为匹配 *.h 或 *.cpp 的目录中的每个文件名添加一个前缀字符串。但是，如果前缀已应用于文件名，请不要再次应用它。
Why the following doesn't work is something that has yet to be figured out:
为什么以下不起作用是尚未弄清楚的事情：
for i in *.{h,cpp}
do
if [[ $i!="$pattern*" ]]
then mv $i $pattern$i
fi
done
采纳答案by codaddict
you can try this:
你可以试试这个：
for i in *.{h,cpp}
do
if ! ( echo $i | grep -q "^$pattern" )
# if the file does not begin with $pattern rename it.
then mv $i $pattern$i
fi
done
回答by Gordon Davisson
Others have shown replacements comparisons that work; I'll take a stab at why the original version didn't. There are two problems with the original prefix test: you need spaces between the comparison operator (!=) and its operands, and the asterisk was in quotes (meaning it gets matched literally, rather than as a wildcard). Fix these, and (at least in my tests) it works as expected:
其他人已经展示了有效的替代比较；我会尝试一下为什么原始版本没有。原始前缀测试有两个问题：比较运算符 ( !=) 与其操作数之间需要空格，并且星号在引号中（意味着它按字面匹配，而不是作为通配符）。修复这些，并且（至少在我的测试中）它按预期工作：
if [[ $i != "$pattern"* ]]
回答by DigitalRoss
#!/bin/sh
pattern=testpattern_
for i in *.h *.cpp; do
case "$i" in
$pattern*)
continue;;
*)
mv "$i" "$pattern$i";;
esac
done
This script will run in any Posix shell, not just bash. (I wasn't sure if your question was "why isn't this working" or "how do I make this work" so I guessed it was the second.)
该脚本将在任何 Posix shell 中运行，而不仅仅是 bash。（我不确定您的问题是“为什么这不起作用”或“我如何使其起作用”，所以我猜是第二个。）
回答by falstro
for i in *.{h,cpp}; do
[ ${i#prefix} = $i ] && mv $i prefix$i
done
Not exactly conforming to your script, but it should work. The check returns true if there is no prefix (i.e. if $i, with the prefix "prefix" removed, equals $i).
不完全符合您的脚本，但它应该可以工作。如果没有前缀，检查返回真（即，如果 $i，去掉前缀“prefix”，等于 $i）。
