[xiluhua@vm-xiluhua][~/shell_script]$ cat forDemo1.sh

#=======================================================================================

#/bin/bash

#auth: xiluhua

#date:

#desc: print file list in a directory

#=======================================================================================

[ -z $ ] && echo "exception@1: directory can not be null" && exit 

echo "prompt: print file list in a directory ..."

for file in $(ls $/*.123)

do

        echo $file

done

exit 0

[xiluhua@vm-xiluhua][~/shell_script]$ cat forDemo2.sh

#=======================================================================================

#/bin/bash

#auth: xiluhua

#date:

#desc: print triangle with *

#=======================================================================================

for (( i=; i<; i++ ))

do

    let space=-$i

        #echo $space

        for (( j=; j<${space}; j++ ))

        do

                printf " "

        done

        let star=*$i+

        for (( k=; k<$star; k++ ))

    do

        printf "*"

    done

        echo ""

done