第一個腳本文件
代碼如下:
#!/bin/bash
echo "This is my first bash code!"
exit 0

重定向符號和數學計算
代碼如下:
#!/bin/bash
echo -n "The time and date are: "
date
value1=100  #等號前后不允許出現空格
value2=$value1
echo -n "value1="
echo $value1
echo -n "value2="
echo $value2
ls -l | sort > out.txt   #管道符號(|)和重定向輸出符號>
ls -l >> out.txt   #重定向追加輸出符號>>
echo -n  "wc<out.txt:"
wc < out.txt  #重定向輸入符號<
echo "sort<<EOF ... EOF"
sort << EOF  #內置輸入重定向<<
`date`
EOF
#數學計算
echo -n "expr進行計算：1+5="
expr 1+5
echo -n "使用方括號進行計算：1+5="
echo $[1+5]
echo "使用bc計算器進行浮點運算"
var1=100
var2=200
var3=`echo "scale=4;$var1/$var2" | bc`
echo "$var1 / $var2 = $var3"
var4=71
var5=`bc<<EOF
scale=4
a1=($var1*$var2)
b1=($var3*$var4)
a1+b1
EOF`
echo "var5=$var5"
exit 0

使用test命令
代碼如下:
#!/bin/bash
#使用test命令
var1=10
var2=100
if [ $var1 -gt $var2 ]
then
    echo "var1 grate var2"
else
    echo "var2 grate var1"
fi
#只能比較整數
test_user=hanxi
if [ $USER = $test_user ]
then
    echo "Welcome $test_user"
fi
str1=Hanxi
str2=hanxi
if [ $str1 /> $str2 ]
then
    echo "$str1 > $str2"
else
    echo "$str1 < $str2"
fi
if [ -n $str1 ]
then
    echo "The string '$str1' is not empty"
else
    echo "the string '$str1' is empty"
fi
#檢查文件目錄
if [ -d $HOME ]
then
    echo "your Home dir exists"
    cd $HOME
    ls -a
else
    echo "there's a problem with your HOME dir"
fi
pwfile=/etc/shadow
if [ -f $pwfile ]
then
    if [ -r $pwfile ]
    then
        tail $pwfile
    else
        echo "Sorry, I'm unable to reas the $pwfile file "
    fi
else
    echo "Sorry, the file $pwfile doesn't exist"
fi
if [[ $USER == h* ]]
then
    echo "Hello $USER"
else
    echo "Sorry, I don't know you"
fi

循環語句
代碼如下:
#!/bin/bash
for file in /home/hanxi/*
do
    if [ -d "$file" ]
    then
        echo "$file is a directory"
    elif [ -f "$file" ]
    then
        echo "$file is a file"
    fi
done
var1=10
while [ $var1 -gt 0 ]
do
    echo $var1