bash 带通配符的文件循环
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File loop with wildcard
提问by user2965857
I'm writing a small script, for starting scripts created in the background. This script is running in a loop and has to start the created file when it is found in the specified directory.
我正在编写一个小脚本，用于启动在后台创建的脚本。此脚本循环运行，并且必须在指定目录中找到创建的文件时启动该文件。
It works when only one file is in the directory, the created script removes itself when it's finisched. But when 2 or more scripts are created at the same time it failes to run the scripts.
当目录中只有一个文件时，它起作用，创建的脚本在完成时会自行删除。但是当同时创建 2 个或更多脚本时，它无法运行脚本。
I get a error : binary operator expected
我收到一个错误：预期的二元运算符
#!/bin/bash
files="/var/svn/upload/*.sh"
x=1
while :
do
echo Sleeping $x..
if [ -f $files ]
then
for file in $files
do
echo "Processing $file file..."
sh $file
echo $(date +%d-%m-%y) $(date +%H:%M:%S) - Sleep $x - Script $f >>/var/log/upload.log
x=0
wait
done
fi
x=$(( $x + 1 ))
sleep 1
done
I created a work around wich is working without any problems:
我创建了一个解决方法，它可以正常工作：
#!/bin/bash
files="/var/upload/*.sh"
x=1
while :
do
count=$(ls $files 2> /dev/null | wc -l)
echo Sleeping $x..
if [ "$count" != "0" ]
then
for file in $files
do
echo "Processing $file file..."
sh $file
echo $(date +%d-%m-%y) $(date +%H:%M:%S) - Sleep $x - Script $f >>/var/log/upload.log
x=0
wait
done
fi
x=$(( $x + 1 ))
sleep 1
done
回答by chepner
The -foperator applies to only a single file, not the list that results by expanding your unquoted $files. If you really need to capture the full list of files in a single variable, use an array, not a string. The nullgloboption ensures that filesis truly empty if the glob fails to match any files, eliminating the need for the -ftest. There is also no need to call wait, as you aren't starting any background jobs.
该-f运算符仅适用于单个文件，而不适用于扩展未加引号的$files. 如果您确实需要在单个变量中捕获完整的文件列表，请使用数组，而不是字符串。如果 glob 无法匹配任何文件，该nullglob选项可确保它files真正为空，从而无需进行-f测试。也无需调用wait，因为您没有启动任何后台作业。
#!/bin/bash
shopt -s nullglob
x=1
while :
do
echo Sleeping $x..
for file in /var/svn/upload/*.sh
do
echo "Processing $file file..."
sh "$file"
echo $(date +%d-%m-%y) $(date +%H:%M:%S) - Sleep $x - Script "$f" >>/var/log/upload.log
x=0
done
x=$(( $x + 1 ))
sleep 1
done
回答by Yushin Washio
One potential source of a similar problem is when the files matching the wildcard do not exist. In that case it just handles the word containint the *as such.
类似问题的一个潜在来源是与通配符匹配的文件不存在时。在这种情况下，它只是处理单词 containsint*本身。
$ touch exist{1,2} alsoexist1
$ for file in exist* alsoexist* notexist* neitherexist*
> do echo $file
> done
exist1
exist2
alsoexist1
notexist*
neithereixt*
