shell脚本学习（一）

test：简单命令的组合

#!/bin/bash date who 结果： 2019年 11月 01日 星期五 10:34:27 CST tty1 2019-10-17 01:40 (:0) pts/2 2019-11-01 09:03 (10.4.205.170)

test1：echo的使用

#!/bin/bash echo The time and date are: date echo Look who is on the system: who echo ----------------------------------------------------- echo -n "The time and date are: " date 结果： The time and date are: 2019年 11月 01日 星期五 10:34:41 CST Look who is on the system: tty1 2019-10-17 01:40 (:0) pts/2 2019-11-01 09:03 (10.4.205.170) ----------------------------------------------------- The time and date are: 2019年 11月 01日 星期五 10:34:41 CST

test2：$的使用

#!/bin/bash echo User :$USER echo UserID:$UID echo HOME :$HOME echo ------------------------- echo Show time $15 echo Show time \$15 结果： User : UserID:1588318 HOME :/home/ ------------------------- Show time 5 Show time $15

test3：自定义变量

#!/bin/bash user1="XT" user2="Sam" day1=10 day2=$day1 echo $user1 checked in $day1 days ago! echo $user2 checked in $day2 days ago! 结果： XT checked in 10 days ago! Sam checked in 10 days ago!

test4：数学运算应用

#!/bin/bash var1=10 var2=5 var3=1 var4=$[$var1 * ($var2 - $var3)] echo var4=$var4 结果： var4=40

test5：if-then-fi

#!/bin/bash if pwd then echo "if-then-fi worked!" fi 结果： /home//shell if-then-fi worked!

test6：if-then-else-fi

#!/bin/bash if psl then echo "if-then-fi worked!" else echo "Not work!" fi 结果： ./test8:行2: psl: 未找到命令 Not work!

test7：if-then-elif-then-fi

#!/bin/bash if psl then echo "psl worked!" elif pwd then echo "pwd work!" fi 结果： ./test9:行2: psl: 未找到命令 /home//shell pwd work!

test8：if-test-then-else-fi

#!/bin/bash var="Full" if test $var then echo "var not NULL" else echo "var is NULL!" fi 结果： var not NULL