问题描述
我有一个检查0大小的脚本，但是我认为必须有一种更简单的方法来检查文件大小. IE. file.txt通常为100k；如何制作脚本以检查脚本是否小于90k(包括0)，并使其获得新的副本，因为在这种情况下文件已损坏.
I've got a script that checks for 0-size, but I thought there must be an easier way to check for file sizes instead. I.e. file.txt is normally 100k; how to make a script check if it is less than 90k (including 0), and make it do wget a new copy because the file is corrupt in this case.
我目前正在使用什么.
if [ -n file.txt ]
then
echo "everything is good"
else
mail -s "file.txt size is zero, please fix. " [email protected] < /dev/null
# Grab wget as a fallback
wget -c https://www.server.org/file.txt -P /root/tmp --output-document=/root/tmp/file.txt
mv -f /root/tmp/file.txt /var/www/file.txt
fi
推荐答案
[ -n file.txt ]不检查其大小，而是检查字符串file.txt的长度是否为非零，因此它将始终成功.
[ -n file.txt ] doesn't check its size, it checks that the string file.txt is non-zero length, so it will always succeed.
如果要说大小不为零"，则需要[ -s file.txt ].
If you want to say "size is non-zero", you need [ -s file.txt ].
要获取文件的大小，可以使用wc -c获取以字节为单位的大小(文件长度):
To get a file's size, you can use wc -c to get the size (file length) in bytes:
file=file.txt
minimumsize=90000
actualsize=$(wc -c <"$file")
if [ $actualsize -ge $minimumsize ]; then
echo size is over $minimumsize bytes
else
echo size is under $minimumsize bytes
fi
在这种情况下，听起来就是您想要的.
In this case, it sounds like that's what you want.
但是，仅供参考，如果您想知道文件正在使用多少磁盘空间，可以使用du -k来获取大小(已使用的磁盘空间)以千字节为单位.
But FYI, if you want to know how much disk space the file is using, you could use du -k to get the size (disk space used) in kilobytes:
file=file.txt
minimumsize=90
actualsize=$(du -k "$file" | cut -f 1)
if [ $actualsize -ge $minimumsize ]; then
echo size is over $minimumsize kilobytes
else
echo size is under $minimumsize kilobytes
fi
如果您需要对输出格式的更多控制，还可以查看stat.在Linux上，您将以stat -c '%s' file.txt之类的东西开始，而在BSD/Mac OS X上，您将以stat -f '%z' file.txt之类的东西开始.
If you need more control over the output format, you can also look at stat. On Linux, you'd start with something like stat -c '%s' file.txt, and on BSD/Mac OS X, something like stat -f '%z' file.txt.
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