Distinguish between command line parameter passing exercises and user input parameters
1,
Create a file named foo.sh Script for , Let it provide the following features
A. When running /root/foo.sh redhat, Output as fedora
B. When running /root/foo.sh fedora, Output as redhat
C. When there is no parameter or the parameter is not redhat perhaps fedora Time , Prompt to output the following information ：/root/foo.sh redhat|fedora
no need bash Method of program name , It is required to write clearly how to implement it .
touch foo.sh
vi foo.sh
#!/bin/bash
if [ "$1" = redhat ];
then echo 'fedora'
elif [ "$1" = fedora ];
then echo 'redhat'
else echo "/root/foo.sh redhat|fedora"
fi
:wq
chmod 755 foo.sh
./foo.sh redhat
2, Write a script file checkuser, When the script runs, it gets the user name entered by the user , stay /etc/passwd Find whether the user exists in the file . Tips ：cut
/etc/passwd -d: -f1
touch checkuser
vi checkuser
#!/bin/bash
echo ' enter one user name '
read username
i=`cut /etc/passwd -d: -f1 |grep -c $username`
if [ "$i" = "1" ];
then echo ' This user exists '
else echo ' This user does not exist '
fi
3.
Write a script to back up the files specified by the user （ How to get user input customization ）, Back up the files to the directory under backup In the directory （ If the directory does not exist, it will be created automatically ）, The file name format of the backup file is “ file name _bak_ specific date _ Hour, minute and second ”.
touch bak.sh
chmod 777 bak.sh
#!/bin/bash
echo ' enter path '
read filepath
dirs=`ls ~ | grep -c 'backup'`
if [ "$dirs" = "0" ];
then `mkdir backup`
fi
bakpath="/root/backup/"
if [ -f $filepath ];
then
cp $filepath $bakpath`basename $filepath`_bak_`date '+%Y%m%d_%H%M%S'`
else echo " file does not exist "
fi
practice case control structure
4. Write a shell Script program , It can take different actions according to the input command line parameters ： If it is a directory , Then the files in the directory are listed ; If it is an executable file , Then use shell Executive ; If it is a readable file , Then the content is displayed in separate screens .
touch four.sh
Direct use if
#!/bin/bash
file=$1
if [ -d $file ];
then ls $file
elif [ -x $file ];
then sh $file
elif [ -r $file ];
then more $file
else ll $file
fi
Second case+if
#!/bin/bash
file=$1
n=0
if [ -d $file ];
then n=1
elif [ -x $file ];
then n=2
elif [ -r $file ];
then n=3
else n=4
fi
case $n in
1) ls $file;;
2) sh $file;;
3) more $file;;
4) ll $file;;
esac
Practice loop control structure
5. All files in the given directory of the user mp3 File name change , The name is preceded by a number （ increase +1 that will do ）. Require the user to pass the given directory read Input statement get .
Tips ： $[],$(())
#!/bin/bash
echo ' Input directory '
read dirpath
files=`ls $dirpath/*.mp3`
num=1
for m in $files
do
mv "$dirpath/`basename $m`" "$dirpath/${num}`basename $m`"
num=$((num+1))
done
File directory operation script writing exercise
6. Under the home directory fd Backup directory data , Requires that you always keep the most recent 3 Backup times . The data to be backed up is stored in /home/user/workdata in , The last three backup files are named worknewdata.tar,work2nddata.tar and work3rddata.tar.
#!/bin/bash
num=`ls ${HOME}/workdata | grep -c "work*"`
change()
{
mv ~/workdata/work2nddata.tar ~/workdata/work3rddata.tar
mv ~/workdata/worknewdata.tar ~/workdata/work2nddata.tar
tar -Pczf ~/workdata/worknewdata.tar ~/fd
}
if [ $num -eq 3 ];
then
`rm -f ~/workdata/work3rddata.tar`
change
elif [ $num -eq 2 ];
then change
elif [ $num -eq 1 ];
then
mv ~/workdata/worknewdata.tar ~/workdata/work2nddata.tar
tar -cPzf ~/workdata/worknewdata.tar ~/fd
else tar -cPzf ~/workdata/worknewdata.tar ~/fd
fi
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