1 . Script format
Script #! / Bin / bash at the beginning (designated analytical unit )
2 . The first Shell Script : helloworld
( 1 ) Demand: Creating a Shell script, output helloworld
( 2 ) Case practical operation:
[atguigu@hadoop101 datas]$ touch helloworld.sh
[Atguigu @ hadoop101 datas] $ vi helloworld.sh
In helloworld.sh enter the following in
#!/bin/bash
echo "helloworld"
( 3 ) common implementation of the script
Di Yi species: using bash or sh + script of a relative or absolute path (not given script + x permission)
sh + phase script on path
[atguigu@hadoop101 datas]$ sh helloworld.sh
Helloworld
sh + script absolute path
[atguigu@hadoop101 datas]$ sh /home/atguigu/datas/helloworld.sh
helloworld
bash + scripting relative path
[atguigu@hadoop101 datas]$ bash helloworld.sh
Helloworld
bash + scripting the absolute path
[atguigu@hadoop101 datas]$ bash /home/atguigu/datas/helloworld.sh
Helloworld
First dicarboxylic kinds: using the input script absolute or relative path to execute the script ( must have executable rights + X )
( A ) First, we want to give helloworld.sh script + x permissions
[atguigu@hadoop101 datas]$ chmod 777 helloworld.sh
( B ) execution of the script
Relative path
[atguigu@hadoop101 datas]$ ./helloworld.sh
Helloworld
Absolute path
[atguigu@hadoop101 datas]$ /home/atguigu/datas/helloworld.sh
Helloworld
Note: The first execution method, nature is bash parser to help you execute the script, so the script itself does not need execute permissions. Di two kinds execution method, essentially a script needs its own execution , the order requires execute permissions.
3. Di Er Ge Shell Scripting : Multi-command processing
( 1 ) Demand :
In / home / atguigu / directory created under a banzhang.txt, banzhang.txt file in an increase in the "I love cls".
( 2 ) Case practical operation:
[atguigu@hadoop101 datas]$ touch batch.sh
[Atguigu @ hadoop101 datas] $ vi batch.sh
In batch.sh enter the following in
#!/bin/bash
cd /home/atguigu
touch cls.txt
echo "I love cls" >>cls.txt