#!/bin/bash
#when i test my code -ex-xe-e-x these drop are not useful and inspire a error
#第一行表示锁定解释器，#！表示不忽略此条
# remember to chmod 755 yourscript.sh,no need of ./
# then you tap ./yourscript.sh to run this .sh file
# finally you will see your answer
#echo "My First Script!"
#echo表示向终端输出内容。
read -p "Please Enter Your Name:" NAME
#read giveNAME (variable) some context.
echo "$(hostname)"
echo "NAME = "st""
if [ $NAME = "yay" ]
#need $ to declare your variable.
then
echo "my host:)"
else
echo "you are a bad guy:("
fi
case "$NAME" in
[yY][Aa][yY] | [yY])
echo ":)"
;;
*)
echo ":("
;;
esac
COLORS="red green blue"
#Captical alpha differs system function.
for COLOR in $COLORS
#NO need[]
do
echo "color is：${COLOR}"
### 顶端
do
echo "color is：${COLOR}"
done
#when you are giving some context to this variable
# do not use this plain input.
FILES=$(ls *txt)
#* is equal to all.
NEW="new"
for FILE in $FILES
do
echo "renaming $FILE to new-$FILE"
#Tell your enemy to join this war.
mv $FILE $NEW-$FILE
#mv is meaning changing name?txt the docu?
done
# all loop function has the same struct.
# for conditon(no need of []
#do
#done
#continue is to break current loop
# break is to break whole loop setence/
#NAME can be used through all the .sh file.
# from 0---while 0 is to this script.sh.1- defined variable.
# same to c++,while main is completr correctly /return 0.
# to check wheather the function is conducted right.
#LINE = 1
#while read CURRENT_LINE
#do
# echo"$LINE:$CURRENT_LINE"
# ((LINE++))
#done </etc/passwd
# read function i dont konw
# CURRRENT_LINE,LINE is random name?
## 43,0-1 74%
# end this etc/passwd ,why?
HOST="google.com"
ping -c 1 $HOST
RETURN_CODE=$?
# Result is saved in this $? variable.amazing.
if [ "RETURN_CODE" -eq "0" ]
then
echo "$HOST is reachable."
else
echo "$HOST is unreachabe."
fi
