blocks|key|1660169|text|我想你会说“$file的最后四个字符是否等于.txt?”如果是这样，您可以使用以下命令：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1660170|if+[+"${file:+-4}"+==+".txt"+]|code-block|syntax|javascript|1660171|请注意，file:和-4之间的空格是必需的，因为':-‘修饰符的含义不同。|1660172|entityMap^0|M|4|0|0|4|5|A|2|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

I think you want to say &quot;Are the last four characters of $file equal to <code>.txt</code>?&quot; If so, you can use the following:
<pre><code>if [ &quot;${file: -4}&quot; == &quot;.txt&quot; ]
</code></pre>
Note that the space between <code>file:</code> and <code>-4</code> is required, as the ':-' modifier means something different.

blocks|key|1445484|text|制作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1445485|if+[+"$file"+==+"*.txt"+]|code-block|syntax|javascript|1445486|如下所示：|1445487|if+[[+$file+==+*.txt+]]|1445488|也就是说，双括号和无引号。|1445489|==的右侧是一个外壳模式。如果需要正则表达式，则使用=~。|offset|length|style|CODE|1445490|entityMap^0|0|0|0|0|0|0|2|Q|2|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@$O|10|P|11|Q|R]|$O|12|P|13|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|T|$]]

Make 

<pre><code>if [ "$file" == "*.txt" ]
</code></pre>

like this:

<pre><code>if [[ $file == *.txt ]]
</code></pre>

That is, double brackets and no quotes.

The right side of <code>==</code> is a shell pattern.
If you need a regular expression, use <code>=~</code> then.

blocks|key|1445427|text|在Unix系统上，你不能确定.txt文件是否真的是一个文本文件。最好的办法是使用"file“。也许可以尝试使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1445428|file+-ib+"$file"|code-block|syntax|javascript|1445429|然后，您可以使用MIME类型列表来匹配或解析MIME的第一部分，在那里您可以获得"text“、"application”等内容。|1445430|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You just can't be sure on a Unix system, that a .txt file truly is a text file. Your best bet is to use "file". Maybe try using:

<pre><code>file -ib "$file"
</code></pre>

Then you can use a list of MIME types to match against or parse the first part of the MIME where you get stuff like "text", "application", etc.

blocks|key|1660354|text|您还可以执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1660355|+++if+[+"${FILE##*.}"+=+"txt"+];+then
+++++++#+operation+for+txt+files+here
+++fi|code-block|syntax|javascript|1660356|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You could also do:

<pre><code> if [ "${FILE##*.}" = "txt" ]; then
 # operation for txt files here
 fi
</code></pre>

blocks|key|1660138|text|如果你真的想找出关于文件的信息而不是依赖于扩展名，你可以使用"+file“命令。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1660139|如果您对扩展的使用感到满意，可以使用grep查看它是否匹配。|1660140|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

You can use the "file" command if you actually want to find out information about the file rather than rely on the extensions.

If you feel comfortable with using the extension you can use grep to see if it matches.

blocks|key|1660467|text|与'+file‘类似，使用稍微简单一点的'mimetype+-b’，无论文件扩展名是什么，它都可以工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1660468|if+[+$(mimetype+-b+"$MyFile")+==+"text/plain"+]
then
++echo+"this+is+a+text+file"
fi|code-block|syntax|javascript|1660469|编辑:如果mimetype不可用，您可能需要在系统上安装libfile-mimeinfo-perl|1660470|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Similar to 'file', use the slightly simpler 'mimetype -b' which will work no matter the file extension.

<pre><code>if [ $(mimetype -b "$MyFile") == "text/plain" ]
then
 echo "this is a text file"
fi
</code></pre>

Edit: you may need to install libfile-mimeinfo-perl on your system if mimetype is not available

blocks|key|1660516|text|关于如何使用linux文件名中可用的扩展名，正确答案是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1660517|${filename##*\.}+|code-block|syntax|javascript|1660518|打印目录中所有文件扩展名的示例|1660519|for+fname+in+$(find+.+-maxdepth+1+-type+f)+#+only+regular+file+in+the+current+dir
++++do++echo+${fname##*\.}+#print+extensions+
done|1660520|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The correct answer on how to take the extension available in a filename in linux is:

<pre><code>${filename##*\.} 
</code></pre>

Example of printing all file extensions in a directory 

<pre><code>for fname in $(find . -maxdepth 1 -type f) # only regular file in the current dir
 do echo ${fname##*\.} #print extensions 
done
</code></pre>

blocks|key|1660342|text|我写了一个bash脚本来查看文件的类型，然后将其复制到一个位置，我使用它来查看我从firefox缓存中在线观看的视频：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1660343|#!/bin/bash
#+flvcache+script

CACHE=~/.mozilla/firefox/xxxxxxxx.default/Cache
OUTPUTDIR=~/Videos/flvs
MINFILESIZE=2M

for+f+in+`find+$CACHE+-size+%2B$MINFILESIZE`
do
++++a=$(file+$f+%7C+cut+-f2+-d+'+')
++++o=$(basename+$f)
++++if+[+"$a"+=+"Macromedia"+]
++++++++then
++++++++++++cp+"$f"+"$OUTPUTDIR/$o"
++++fi
done

nautilus++"$OUTPUTDIR"&|code-block|syntax|javascript|1660344|它使用了与这里介绍的类似的想法，希望这对某些人有帮助。|1660345|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I wrote a bash script that looks at the type of a file then copies it to a location, I use it to look through the videos I've watched online from my firefox cache:

<pre><code>#!/bin/bash
# flvcache script

CACHE=~/.mozilla/firefox/xxxxxxxx.default/Cache
OUTPUTDIR=~/Videos/flvs
MINFILESIZE=2M

for f in `find $CACHE -size +$MINFILESIZE`
do
 a=$(file $f | cut -f2 -d ' ')
 o=$(basename $f)
 if [ "$a" = "Macromedia" ]
 then
 cp "$f" "$OUTPUTDIR/$o"
 fi
done

nautilus "$OUTPUTDIR"&amp;
</code></pre>

It uses similar ideas to those presented here, hope this is helpful to someone.

blocks|key|1660407|text|我猜'$PATH_TO_SOMEWHERE'有点像'<directory>/*'。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1660408|在本例中，我将代码更改为：|1660409|find+<directory>+-maxdepth+1+-type+d+-exec+...+\;
find+<directory>+-maxdepth+1+-type+f+-name+"*.txt"+-exec+...+\;|code-block|syntax|javascript|1660410|如果您想对目录和文本文件名执行更复杂的操作，您可以：|1660411|find+<directory>+-maxdepth+1+-type+d+%7C+while+read+dir;+do+echo+$dir;+...;+done
find+<directory>+-maxdepth+1+-type+f+-name+"*.txt"+%7C+while+read+txtfile;+do+echo+$txtfile;+...;+done|1660412|如果文件名中有空格，则可以：|1660413|find+<directory>+-maxdepth+1+-type+d+%7C+xargs+...
find+<directory>+-maxdepth+1+-type+f+-name+"*.txt"+%7C+xargs+...|1660414|entityMap^0|2|K|P|F|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|15|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|U|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|V|$]]

I guess that <code>'$PATH_TO_SOMEWHERE'</code>is something like <code>'&lt;directory&gt;/*'</code>.

In this case, I would change the code to:

<pre><code>find &lt;directory&gt; -maxdepth 1 -type d -exec ... \;
find &lt;directory&gt; -maxdepth 1 -type f -name "*.txt" -exec ... \;
</code></pre>

If you want to do something more complicated with the directory and text file names, you could:

<pre><code>find &lt;directory&gt; -maxdepth 1 -type d | while read dir; do echo $dir; ...; done
find &lt;directory&gt; -maxdepth 1 -type f -name "*.txt" | while read txtfile; do echo $txtfile; ...; done
</code></pre>

If you have spaces in your file names, you could:

<pre><code>find &lt;directory&gt; -maxdepth 1 -type d | xargs ...
find &lt;directory&gt; -maxdepth 1 -type f -name "*.txt" | xargs ...
</code></pre>

I am writing a nightly build script in bash. 
Everything is fine and dandy except for one little snag:

<pre><code>
#!/bin/bash

for file in "$PATH_TO_SOMEWHERE"; do
 if [ -d $file ]
 then
 # do something directory-ish
 else
 if [ "$file" == "*.txt" ] # this is the snag
 then
 # do something txt-ish
 fi
 fi
done;
</code></pre>

My problem is determining the file extension and then acting accordingly. I know the issue is in the if-statement, testing for a txt file. 

How can I determine if a file has a .txt suffix?

How to check the extension of a filename in a bash script?

Unix

我正在用bash编写一个夜间构建脚本。一切都很好，除了一个小问题：#!/bin/bashfor file in "$PATH_TO_SOMEWHERE"; do      if [ -d $file ]      then              # do something directory-ish      else              if [ "$file" == "*.txt"

问如何在bash脚本中检查文件名的扩展名？
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问如何在bash脚本中检查文件名的扩展名？
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