关于shell中的for循环用法很多,一直想总结一下,今天网上看到上一篇关于for循环用法的总结,感觉很全面,所以就转过来研究研究,嘿嘿...
for((i=1;i<=10;i++));do echo $(expr $i \* 4);done
for i in `ls` for i in ${arr[@]} for i in $* ; do for File in /proc/sys/net/ipv4/confaccept_redirects:' for File in /proc/sys/net/ipv4/conf/*/accept_redirects; do echo $File done echo "直接指定循环内容" for i in f1 f2 f3 ;do echo $i done echo echo "C 语法for 循环:" for (( i=0; i<10; i++)); do echo $i done
shell语法好麻烦的,一个循环都弄了一会 ,找了几个不同的方法来实现输出1-100间可以被3整除的数
1.用(())
#!/bin/bash clear for((i=1;i<100;i++)) for do if((i%3==0)) then echo $i continue fi done
#!/bin/bash clear for i in `seq 100` do if((i%3==0)) then echo $i continue fi done
#!/bin/bash clear i=1 while(($i<100)) do if(($i%3==0)) then echo $i fi i=$(($i+1)) done
for i in `seq 1 1000000`;do echo $i done
for((i=1;i<10000000;i++));do echo $i done 3. i=1 while(($i<10000000));do echo $i i=`expr $i + 1` done
for i in {1..10000000;do echo $i done
# !/bin/sh i=1 function test_while(){ i=1 while [ $i ] do echo $i i=`expr $i + 1` if [ $i -ge 10 ]; then break fi done } function test_for(){ i=1 for ((i=1; i<=100; i++)); do echo $i if [ $i -ge 10 ]; then break fi done } function test_continue(){ i=1 for i in $(seq 100); do if (( i==0 )); then echo $i continue fi done } echo "test_while..." test_while echo "test_for..." test_for echo "test_continue..." test_continue
test_while... 1 2 3 4 5 6 7 8 9 test_for... 1 2 3 4 5 6 7 8 9 10 test_continue... 10 20 30 40 50 60 70 80 90 100