Shell integrated application cases, archiving files, sending messages

1. The archive

In practical production application , It is often necessary to archive and back up important data .
demand : Implement a script that archives and backs up the specified directory every day , Enter a directory name ( It doesn't end with /), Archive and save all files in the directory on a daily basis , And attach the filing date to the file name , Put it in /root/archive Next .
The archive command is used here : tar
You can add -c Option means archive , add -z Option means to compress at the same time , The resulting file suffix is .tar.gz

1.1 Script implementation

#!/bin/bash

# First, judge whether the number of input parameters is 1
if [ $# -ne 1 ]
then
        echo " Wrong number of parameters ！ You should enter a parameter , As the archive directory name "
        exit
fi

#  Get the directory name from the parameter 
if [ -d $1 ]
then
        echo
else
        echo
        echo " directory does not exist ！"
        echo
        exit
fi

DIR_NAME=$(basename $1)
DIR_PATH=$(cd $(dirname $1); pwd)

#  Get current date 
FILE=archive_${
    DIR_NAME}_$DATE.tar.gz
DEST=/root/archive/$FILE

#  Start archiving catalog files 

echo " Start filing ..."
echo

tar -czf $DEST $DIR_PATH/$DIR_NAME

if [ $? -eq 0 ]
then
        echo
        echo " Archive success ！"
        echo " Archive file is ：$DEST"
        echo
else
        echo " There is a problem with archiving !"
        echo
fi

exit

1.2 test

Then create a file

Archive success

1.3 Regular filing

Use crontab
crontab The code in

0 2 * * * /root/scripts/daily_archive.sh /root/scripts

2. Send a message

This allows you to view users' online status , + Number represents that you can send messages ,mesg It's open

mesg n Can be mesg close
mesg y Can be mesg open

2.1write Send a message

• write user name Console
  [[email protected] scripts]# write cat pts/1

We can use Linux Self contained mesg and write Tools , Send messages to other users .
demand ： Implement a script to quickly send messages to a user , Enter the user name as the first parameter , Followed directly by the message to be sent . The script needs to detect whether the user logs in to the system 、 Whether to turn on the message function , And whether the currently sent message is empty .
The script is implemented as follows ：

#!/bin/bash

#  Check whether the user is logged in 
login_user=$(who | grep -i -m 1 $1 | awk '{print $1}')

if [ -z $login_user ]
then
        echo "$1  Not online !"
        echo " Script exit ..."
        exit
fi

#  Check whether the user turns on the message function 
is_allwoed=$(who -T | grep -i -m 1 $1 | awk '{print $2}')


if [ "$is_allowed"x != "+"x ]
then
        echo "$1  No message function is enabled "
        echo " Script exit ..."
        exit
fi

#  Confirm whether there is a message sent 
if [ -z $2 ]
then
        echo "$1  No message sent "
        echo " Script exit ..."
        exit
fi

#  Get the message to be sent from the parameter 
whole_msg=$(echo $* | cut -d " " -f 2-)

#  Get the terminal where the user logs in 
user_terminal=$(who | grep -i -m 1 $1 | awk '{print $2}')

#  Write the message to send 
echo $whole_msg | write $login_user $user_terminal

if [ $? != 0 ]
then
        echo " fail in send ！"
else
        echo " Send successfully ！"
fi
exit

The end ！！！