Bash-使用循环使备份脚本更有效

1

我有一个备份脚本（bash）。部分内容如下所示。此脚本将备份进行14天的轮换。如果要更改为30天，则必须写出30个if-then块。我确定可以用漂亮的for循环代替。那会是什么？

# step 1: delete the oldest snapshot, if it exists:
if [ -d $BACKUP_DIR/daily.14 ] ; then                   \
$RM -rf $BACKUP_DIR/daily.14 ;                          \
fi ;

# step 2: shift the middle snapshot(s) back by one, if they exist
if [ -d $BACKUP_DIR/daily.13 ] ; then                   \
$MV $BACKUP_DIR/daily.13 $BACKUP_DIR/daily.14 ; \
fi;

if [ -d $BACKUP_DIR/daily.12 ] ; then                   \
$MV $BACKUP_DIR/daily.12 $BACKUP_DIR/daily.13 ; \
fi;

if [ -d $BACKUP_DIR/daily.11 ] ; then                   \
$MV $BACKUP_DIR/daily.11 $BACKUP_DIR/daily.12 ; \
fi;

if [ -d $BACKUP_DIR/daily.10 ] ; then                   \
$MV $BACKUP_DIR/daily.10 $BACKUP_DIR/daily.11 ; \
fi;

if [ -d $BACKUP_DIR/daily.9 ] ; then                    \
$MV $BACKUP_DIR/daily.9 $BACKUP_DIR/daily.10 ;  \
fi;

if [ -d $BACKUP_DIR/daily.8 ] ; then                    \
$MV $BACKUP_DIR/daily.8 $BACKUP_DIR/daily.9 ;   \
fi;

if [ -d $BACKUP_DIR/daily.7 ] ; then                    \
$MV $BACKUP_DIR/daily.7 $BACKUP_DIR/daily.8 ;   \
fi;

if [ -d $BACKUP_DIR/daily.6 ] ; then                    \
$MV $BACKUP_DIR/daily.6 $BACKUP_DIR/daily.7 ;   \
fi;

if [ -d $BACKUP_DIR/daily.5 ] ; then                    \
$MV $BACKUP_DIR/daily.5 $BACKUP_DIR/daily.6 ;   \
fi;

if [ -d $BACKUP_DIR/daily.4 ] ; then                    \
$MV $BACKUP_DIR/daily.4 $BACKUP_DIR/daily.5 ;   \
fi;

if [ -d $BACKUP_DIR/daily.3 ] ; then                    \
$MV $BACKUP_DIR/daily.3 $BACKUP_DIR/daily.4 ;   \
fi;

if [ -d $BACKUP_DIR/daily.2 ] ; then                    \
$MV $BACKUP_DIR/daily.2 $BACKUP_DIR/daily.3 ;   \
fi;

if [ -d $BACKUP_DIR/daily.1 ] ; then                    \
$MV $BACKUP_DIR/daily.1 $BACKUP_DIR/daily.2 ;   \
fi;


# step 3: make a hard-link-only (except for dirs) copy of the latest snapshot, if that exists
if [ -d $BACKUP_DIR/daily.0 ] ; then                    \
$CP -al $BACKUP_DIR/daily.0 $BACKUP_DIR/daily.1 ;       \
fi;

bash

— rc
source

在此发布之前，请尝试至少在Google上搜索一次。有数百个网站向您展示如何完成此任务。

— darnir

1

也许吧，但是我对bash并不陌生，谷歌搜索“ bash loop”并不会产生任何效果（也许会产生任何效果，但是由于我对bash并不十分了解，所以我可能错过了它，或者没有将其挂起适用于此特定情况。不过谢谢！

— Sparctus

1

#!/bin/bash
MAX=29

for i in `seq 1 $MAX` 
do 
    echo " check file exists directory.$i"
    echo "mv directory.$i to directory" `expr $i - 1`
done

这可能是一个很好的起点

— 小妖精
source

谢谢地精为我指出正确的方向。经过一连串的曲折和错误，我能够完成它。您的seq cmd仅递增。我需要一个递减的数字序列。我已经发布了解决方案。再次感谢你。

— Sparctus

sequence命令也可用于减量。您可以使用 seq $MAX -1 1

— 哥布林2012年

0

for i in {7..1};
do
        #echo "$i"

        if [ -d $BACKUP_DIR/daily.${i} ]
        then
                z=$(($i+1));
                #echo "$z"
                echo "moving daily.$i to daily.$z"
                $MV $BACKUP_DIR/daily.$i $BACKUP_DIR/daily.$z ;
        fi;
done

— rc
source