【CentOS 7Shell編程7】，break跳出本次循環和continue結束本次循環以及exit直接退出腳本#180212

hellopasswd

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break跳出本次循環

#!/bin/bash for i in seq 1 5 do echo $i if [ $i == 3] then break fi echo $i done echo a

若比較是字符串，則必須使用==，而不是-eq，純數字則能夠用

[root@localhost shell]# vi 1.sh 
      1 #!/bin/bash
      2 for i in `seq 1 5`
      3 do
      4     echo $i
      5     if [ $i -eq 3 ]
      6     then
      7         break
      8     fi
      9     echo $i
     10 done
     11 echo aaaa

[root@localhost shell]# sh -x 1.sh 
++ seq 1 5
+ for i in '`seq 1 5`'
+ echo 1
1
+ '[' 1 == 3 ']'
+ echo 1
1
+ for i in '`seq 1 5`'
+ echo 2
2
+ '[' 2 == 3 ']'
+ echo 2
2
+ for i in '`seq 1 5`'
+ echo 3
3
+ '[' 3 == 3 ']'
+ break
+ echo aaaa
aaaa
[root@localhost shell]# sh 1.sh 
1
1
2
2
3
aaaa

continue結束本次循環

• 忽略continue之下的代碼，直接進行下一次循環

#!/bin/bash for i in seq 1 5 do echo $i if [ $i == 3] then continue fi echo $i done echo a

[root@localhost shell]# vi 1.sh
      1 #!/bin/bash
      2 for i in `seq 1 5`
      3 do
      4     echo $i
      5     if [ $i == 3 ]
      6     then
      7         continue
      8     fi
      9     echo $i
     10 done
     11 echo aaaa

[root@localhost shell]# sh -x 1.sh 
++ seq 1 5
+ for i in '`seq 1 5`'
+ echo 1
1
+ '[' 1 == 3 ']'
+ echo 1
1
+ for i in '`seq 1 5`'
+ echo 2
2
+ '[' 2 == 3 ']'
+ echo 2
2
+ for i in '`seq 1 5`'
+ echo 3
3
+ '[' 3 == 3 ']'
+ continue
+ for i in '`seq 1 5`'
+ echo 4
4
+ '[' 4 == 3 ']'
+ echo 4
4
+ for i in '`seq 1 5`'
+ echo 5
5
+ '[' 5 == 3 ']'
+ echo 5
5
+ echo aaaa
aaaa
[root@localhost shell]# sh 1.sh 
1
1
2
2
3
4
4
5
5
aaaa

exit直接退出腳本

#!/bin/bash for i in seq 1 5 do echo $i if [ $i == 3 ] then exit fi echo $i done echo aaa

[root@localhost ~]# cd shell/
[root@localhost shell]# vi 1.sh 
      1 #!/bin/bash
      2 for i in `seq 1 5`
      3 do
      4     echo $i
      5     if [ $i == 3 ]
      6     then
      7         exit
      8     fi
      9     echo $i
     10 done
     11 echo aaaa

[root@localhost shell]# sh -x 1.sh 
++ seq 1 5
+ for i in '`seq 1 5`'
+ echo 1
1
+ '[' 1 == 3 ']'
+ echo 1
1
+ for i in '`seq 1 5`'
+ echo 2
2
+ '[' 2 == 3 ']'
+ echo 2
2
+ for i in '`seq 1 5`'
+ echo 3
3
+ '[' 3 == 3 ']'
+ exit
[root@localhost shell]# sh 1.sh 
1
1
2
2
3

[root@localhost shell]# vi 1.sh 
      1 #!/bin/bash
      2 for i in `seq 1 5`
      3 do
      4     echo $i
      5     if [ $i == 3 ]
      6     then
      7         exit 1
      8     fi
      9     echo $i
     10 done
     11 echo aaaa
[root@localhost shell]# sh 1.sh 
1
1
2
2
3
[root@localhost shell]# echo $?
1

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修改於 180228