for循环

语法：for变量名in条件;do...;done

案例1 #!/bin/bash sum=0 for i in seq 1 100 do sum=$[$sum+$i] echo $i done echo $sum

[root@localhost ~]# cd shell/[root@localhost shell]# vi 1.sh      1 #!/bin/bash      2 for i in `seq 1 10`      3 do      4     echo $i      5 done[root@localhost shell]# sh 1.sh 12345678910

[root@localhost shell]# vi 1.sh      1 #!/bin/bash      2 sum=0      3 for i in `seq 1 100`      4 do        5     sum=$[$sum+$i]      6 done      7     echo $sum[root@localhost shell]# sh 1.sh 5050

想知道for语句的计算过程可以添加一个参数-x

[root@localhost shell]# vi 1.sh      1 #!/bin/bash      2 cd /etc/      3 for a in `ls /etc/`      4 do      5     if [ -d $a ]      6     then      7         ls -d $a      8     fi      9 done

遍历

[root@localhost shell]# for i in `seq 1 3`; do echo $i; done123[root@localhost shell]# seq 1 3123[root@localhost shell]# for i in 1 2 3; do echo $i; done123

注意

[root@localhost shell]# mkdir user[root@localhost shell]# cd user/[root@localhost user]# touch 1 2[root@localhost user]# touch 3\ 4[root@localhost user]# ls -ltotal 0-rw-r--r--. 1 root root 0 Feb 10 21:04 1-rw-r--r--. 1 root root 0 Feb 10 21:04 2-rw-r--r--. 1 root root 0 Feb 10 21:04 3 4[root@localhost user]# for i in `ls ./`; do echo $i; done1234