bash 的语法真是反人类啊，反人类啊啊啊

#!/bin/bash

# created: 2015-10-10 13:24:15

size=204800
echo "loop delete oldest log file until directory size < "$size" KB"

while [ 1 ]; do
    directory_size=$(du -s | cut -f1)
    if [ "$size" -gt "$directory_size" ]; then
        echo "break at directory_size "$directory_size" KB"
        break
    else
        echo "directory_size "$directory_size" KB, continue"
    fi
    oldest_log_file=$(ls -tr1 *.log | head -n 1) 
    if [ -z "$oldest_log_file" ]; then
        echo "no more log files to delete, break"
        break
    fi
    echo "deleting "$oldest_log_file"..."
    rm -rf $oldest_log_file
done;

上面没有考虑相对路径问题，crontab 中一般都是绝对路径执行的，修改如下

#!/bin/bash

# created: 2015-10-10 13:24:15

cd /data/log/unified1.0
if [ $? -ne 0 ]; then
    echo "cd dir failed"
    exit -1
fi

size=204800
echo "loop delete oldest log file until directory size < "$size" KB"

while [ 1 ]; do
    directory_size=$(du -s | cut -f1)
    if [ "$size" -gt "$directory_size" ]; then
        echo "break at directory_size "$directory_size" KB"
        break
    else
        echo "directory_size "$directory_size" KB, continue"
    fi
    oldest_log_file=$(ls -tr1 *.log | head -n 1) 
    if [ -z "$oldest_log_file" ]; then
        echo "no more log files to delete, break"
        break
    fi
    echo "deleting "$oldest_log_file"..."
    rm -rf $oldest_log_file
done;

上面的修复还是没有考虑权限，可能出现死循环，修复如下

#!/bin/bash

# created: 2015-10-10 13:24:15

cd /data/log/unified1.0
if [ $? -ne 0 ]; then
    echo "cd dir failed"
    exit -1
fi

size=204800
echo "loop delete oldest log file until directory size < "$size" KB"

while [ 1 ]; do
    directory_size=$(du -s | cut -f1)
    if [ "$size" -gt "$directory_size" ]; then
        echo "break at directory_size "$directory_size" KB"
        break
    else
        echo "directory_size "$directory_size" KB, continue"
    fi
    oldest_log_file=$(ls -tr1 *.log | head -n 1) 
    if [ -z "$oldest_log_file" ]; then
        echo "no more log files to delete, break"
        break
    fi
    echo "deleting "$oldest_log_file"..."
    rm -rf $oldest_log_file
    if [ $? -ne 0 ]; then
        echo "delete file failed"
        break
    fi
    sleep 1
done;