[英]Shell script to delete files when disk is full
I am writing a small little script to clear space on my linux everyday via CRON if the cache directory grows too large.如果缓存目录变得太大,我正在编写一个小的脚本来每天通过 CRON 清除我的 linux 上的空间。 Since I am really green at bash scripting, I will need a little bit of help from you linux gurus out there.
由于我对 bash 脚本编写非常熟悉,因此我需要一些 linux 专家的帮助。
Here is basically the logic (pseudo-code)这里基本上是逻辑(伪代码)
if ( Drive Space Left < 5GB )
{
change directory to '/home/user/lotsa_cache_files/'
if ( current working directory = '/home/user/lotsa_cache_files/')
{
delete files in /home/user/lotsa_cache_files/
}
}
I plan to get the drive space left from the '/dev/sda5' command.我计划从“/dev/sda5”命令中获得剩余的驱动器空间。 If returns the following value to me for your info :
如果将以下值返回给我以获取您的信息:
Filesystem 1K-blocks Used Available Use% Mounted on<br>
/dev/sda5 225981844 202987200 11330252 95% /
So a little regex might be necessary to get the '11330252' out of the returned value因此,可能需要一些正则表达式才能从返回值中获取“11330252”
The 'if ( current working directory = /home/user/lotsa_cache_files/)' part is just a defensive mechanism for the paranoia within me. 'if ( current working directory = /home/user/lotsa_cache_files/)' 部分只是我内心的偏执的防御机制。 I wanna make sure that I am indeed in '/home/user/lotsa_cache_files/' before I proceed with the delete command which is potentially destructive if the current working directory is not present for some reason.
在继续执行删除命令之前,我想确保我确实在“/home/user/lotsa_cache_files/”中,如果由于某种原因当前工作目录不存在,该命令可能具有破坏性。
The deletion of files will be done with the command below instead of the usual rm -f:文件的删除将使用下面的命令而不是通常的 rm -f 来完成:
find . -name "*" -print | xargs rm
This is due to the inherent inability of linux systems to 'rm' a directory if it contains too many files, as I have learnt in the past.这是由于 linux 系统固有的无法“rm”包含太多文件的目录,正如我过去所了解的那样。
Just another proposal (comments within code):只是另一个提议(代码中的评论):
FILESYSTEM=/dev/sda1 # or whatever filesystem to monitor
CAPACITY=95 # delete if FS is over 95% of usage
CACHEDIR=/home/user/lotsa_cache_files/
# Proceed if filesystem capacity is over than the value of CAPACITY (using df POSIX syntax)
# using [ instead of [[ for better error handling.
if [ $(df -P $FILESYSTEM | awk '{ gsub("%",""); capacity = $5 }; END { print capacity }') -gt $CAPACITY ]
then
# lets do some secure removal (if $CACHEDIR is empty or is not a directory find will exit
# with error which is quite safe for missruns.):
find "$CACHEDIR" --maxdepth 1 --type f -exec rm -f {} \;
# remove "maxdepth and type" if you want to do a recursive removal of files and dirs
find "$CACHEDIR" -exec rm -f {} \;
fi
Call the script from crontab to do scheduled cleanings从 crontab 调用脚本来执行预定的清理
I would do it this way:我会这样做:
# get the available space left on the device
size=$(df -k /dev/sda5 | tail -1 | awk '{print $4}')
# check if the available space is smaller than 5GB (5000000kB)
if (($size<5000000)); then
# find all files under /home/user/lotsa_cache_files and delete them
find /home/user/lotsa_cache_files -name "*" -delete
fi
Here's the script I use to delete old files in a directory to free up space...这是我用来删除目录中的旧文件以释放空间的脚本...
#!/bin/bash
#
# prune_dir - prune directory by deleting files if we are low on space
#
DIR=$1
CAPACITY_LIMIT=$2
if [ "$DIR" == "" ]
then
echo "ERROR: directory not specified"
exit 1
fi
if ! cd $DIR
then
echo "ERROR: unable to chdir to directory '$DIR'"
exit 2
fi
if [ "$CAPACITY_LIMIT" == "" ]
then
CAPACITY_LIMIT=95 # default limit
fi
CAPACITY=$(df -k . | awk '{gsub("%",""); capacity=$5}; END {print capacity}')
if [ $CAPACITY -gt $CAPACITY_LIMIT ]
then
#
# Get list of files, oldest first.
# Delete the oldest files until
# we are below the limit. Just
# delete regular files, ignore directories.
#
ls -rt | while read FILE
do
if [ -f $FILE ]
then
if rm -f $FILE
then
echo "Deleted $FILE"
CAPACITY=$(df -k . | awk '{gsub("%",""); capacity=$5}; END {print capacity}')
if [ $CAPACITY -le $CAPACITY_LIMIT ]
then
# we're below the limit, so stop deleting
exit
fi
fi
fi
done
fi
To detect the occupation of a filesystem, I use this :为了检测文件系统的占用,我使用这个:
df -k $FILESYSTEM | tail -1 | awk '{print $5}'
which give me the occupation percentage of the filesystem, this way, I do not need to compute it :)这给了我文件系统的占用百分比,这样,我不需要计算它:)
If you use bash, you can use the pushd/popd operation to change directory and be sure to be in.如果你使用bash,你可以使用pushd/popd操作来改变目录,并且一定要在。
pushd '/home/user/lotsa_cache_files/'
do the stuff
popd
这是我所做的:
while read f; do rm -rf ${f}; done < movies-to-delete.txt
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