实验（七）Shell操作

mkdir 1banz3
# 切到 1banz3 目录：
cd 1banz3

touch SpecialParameter.sh

vi SpecialParameter.sh

#! /bin/bash/
echo "脚本文件名称是: $0"
echo "本条命令的第一个参数是 : $1"
echo "本条命令的第二个参数是 : $2"
echo "本条命令的参数个数是 : $#"
echo "\$* 表示将所有参数看作一个整体 : $*"
for var in "$*"
do
    echo "$var"
done
echo "\$@ 表示将所有参数看作不同的部分 : $@"
for var in "$@"
do
    echo "$var"
done
echo "最后一个进程的ID是 : $$"
echo "上一条命令的结果状态是 : $?"

chmod +x SpecialParameter.sh
./SpecialParameter.sh a b c

bash SpecialParameter.sh a b c

脚本文件名称是: ./SpecialParameter.sh
本条命令的第一个参数是 : a
本条命令的第二个参数是 : b
本条命令的参数个数是 : 3
$* 表示将所有参数看做一个整体 : a b c
a b c
$@ 表示将所有参数不同的部分 : a b c
a
b
c
最后一个进程的ID是 : 1407
上一条命令的结果状态是 : 0

touch ReplaceVar.sh
# 用vi编辑脚本文件
vi  ReplaceVar.sh

username=aaa
echo "now,username=$username"
a=${username:-`whoami`} #:-
echo "a=$a, username=$username"
b=${username:+`whoami`} #:+
echo "b=$b, username=$username"
c=${username:=`whoami`} #:=
echo "c=$c, username=$username"
username=""
echo "now,username=$username"
a=${username:-`whoami`} #
echo "a=$a, username=$username"
username=""
b=${username:+`whoami`} #
echo "b=$b, username=$username"
username=""
c=${username:=`whoami`} #
echo "c=$c, username=$username"
unset username #
echo "now,unset username, so username=$username"
a=${username:-`whoami`} #
echo "a=$a, username=$username"
unset username
b=${username:+`whoami`} #
echo "b=$b, username=$username"
unset username
c=${username:=`whoami`} #
echo "c=$c, username=$username"

bash ReplaceVar.sh

now,username=aaa
a=aaa, username=aaa
b=Administrator, username=aaa
c=aaa, username=aaa
now,username=
a=Administrator, username=
b=, username=
c=Administrator, username=Administrator
now,unset username, so username=
a=Administrator, username=
b=, username=
c=Administrator, username=Administrator

touch ReadAndEcho.sh
# 用vi编辑脚本文件
vi ReadAndEcho.sh

#! /bin/bash
# The first part
read -p "输入一句英文语句:" first second third
echo "第一个参数是 $first"
echo "第二个参数是 $second"
echo "第三个参数是 $third"
# The second part
read -n 4 -t 20 -p "输入一个较长的单词:" word
echo -e "\n$word"
# The third part
echo -e "this\nis\na\ntest"
echo -e "this\tis\ta\ttest"
echo -n "this is a test"
echo ",bye"
echo -e "this is a \ctest"

bash ReadAndEcho.sh

输入一句英文语句:cat eat fish
第一个参数是 cat
第二个参数是 eat
第三个参数是 fish
输入一个较长的单词:mysq
mysq
this
is
a
test
this    is      a       test
this is a test,bye
this is a %