如何检查Bash中是否存在某些文件? [英] How do I check if certain files exist in Bash?
问题描述
在 bash
脚本中,我必须检查是否存在多个文件。
In a bash
script, I have to check for the existence of several files.
我知道这样做很尴尬,如下所示,但这意味着我的主程序必须位于该丑陋的嵌套结构内:
I know an awkward way to do it, which is as follows, but that would mean that my main program has to be within that ugly nested structure:
if [ -f $FILE1 ]
then
if [ -f $FILE2 ]
then
echo OK
# MAIN PROGRAM HERE
fi
fi
以下版本不起作用:
([ -f $FILE1 ] && [ -f $FILE2 ]) || ( echo "NOT FOUND"; exit 1 )
echo OK
打印
NOT FOUND
OK
是否有一种优雅的方法来做到这一点?
Is there an elegant way to do this right?
更新:查看已接受的答案。另外,在优雅方面,我喜欢 Jonathan Leffler的答案:
UPDATE: See the accepted answer. In addition, in terms of elegance I like Jonathan Leffler's answer:
arg0=$(basename $0 .sh)
error()
{
echo "$arg0: $@" 1>&2
exit 1
}
[ -f $FILE2 ] || error "$FILE2 not found"
[ -f $FILE1 ] || error "$FILE1 not found"
推荐答案
怎么样
if [[ ! ( -f $FILE1 && -f $FILE2 ) ]]; then
echo NOT FOUND
exit 1
fi
# do stuff
echo OK
请参见 help [[
和 help test
[[样式测试可用的选项。另请阅读此常见问题解答。
See help [[
and help test
for the options usable with the [[
style tests. Also read this faq entry.
您的版本不起作用,因为(...)
会生成一个新的子shell,在其中执行 exit
。因此,它仅影响该子shell,而不影响执行脚本。
Your version does not work because (...)
spawns a new sub-shell, in which the exit
is executed. It therefor only affects that subshell, but not the executing script.
下面的方法代替了,在 {...}之间执行命令。 code>在当前shell中。
The following works instead, executing the commands between {...}
in the current shell.
我还应该注意,您必须引用两个变量,以确保不会发生不必要的扩展或单词拆分(它们必须作为一个参数传递给 [
)。
I should also note that you have to quote both variables to ensure there is no unwanted expansion or word splitting made (they have to be passed as one argument to [
).
[ -f "$FILE1" ] && [ -f "$FILE2" ] || { echo "NOT FOUND"; exit 1; }
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