Linux 速查表

name="Bash"

name="Bash"
echo $name

readonly name="Bash"
name="Shell"  # 将导致错误

unset name

str1='hello, world'
str2="hello, world"
str3=hello,world

arr=(1 2 3 4 5)

if [ $a == $b ]
then
   echo "a is equal to b"
fi

if [ $a == $b ]
then
   echo "a is equal to b"
else
   echo "a is not equal to b"
fi

if [ $a == $b ]
then
   echo "a is equal to b"
elif [ $a -gt $b ]
then
   echo "a is greater than b"
else
   echo "a is less than b"
fi

for var in 0 1 2 3 4 5 6 7 8 9
do
   echo $var
done

counter=0
while [ $counter -lt 10 ]
do
   echo $counter
   ((counter++))
done

case "$variable" in
abc) echo "\$variable = abc" ;;
xyz) echo "\$variable = xyz" ;;
esac

demoFunction(){
   echo "Hello World!"
}

demoFunction

demoFunction(){
   echo $1
}

demoFunction "Hello"

if [ condition ]
then
    # 执行条件为真时的命令
else
    # 执行条件为假时的命令
fi

num=10
if [ $num -gt 5 ]
then
    echo "Number is greater than 5"
else
    echo "Number is not greater than 5"
fi

for variable in list
do
    # 执行每个元素的命令
done

for i in 1 2 3 4 5
do
   echo "Welcome $i times"
done

while [ condition ]
do
    # 执行条件为真时的命令
done

count=1
while [ $count -le 5 ]
do
   echo "Welcome $count times"
   count=$(( $count + 1 ))
done

function_name () {
    # 函数体
}

greet() {
    echo "Hello, $1"
}

# 调用函数
greet "World"