Application of eval in shell

Application of eval in shell

Eval can be used for nesting of variables

Dr=ddir$inum

Eval ssdir=$ (Echo \$ $SR)

Example:

#!/bin/bash

Date= ' Date +%y%m%d '

Sdir1=/data-to-external/aa

Sdir2=/data-to-external/bb

sdir3=/data-to-external/cc

Ddir1=/historybackup/data-to-external/aa

Ddir2=/historybackup/data-to-external/bb

ddir3=/historybackup/data-to-external/cc

For inum in ' SEQ 1 7 '

Do

Sr=sdir$inum

Dr=ddir$inum

Eval ssdir=$ (Echo \$ $SR)

Eval dddir=$ (Echo \$ $DR)

CD $SSDIR

For job in $ (LS)

Do

If [-D $job];then

Mkdir-p $DDDIR/$Date/$job

MV $job/* $DDDIR/$Date/$job/

Fi

Done

Done

This article is from the "Linux" blog, so be sure to keep this source http://yangzhiming.blog.51cto.com/4849999/1727641

Application of eval in shell