shell相关的用法

Posted 2020-06-09

shell相关的用法

if用法

-q不输出结果，只做判断

[[email protected] tmp]# if grep -q ‘^daixuan:‘ /etc/passwd; then echo "daixuan text" ;fi

，当/etcpasswd下包含daixuan，就输出daixuan test

case用法

[[email protected] tmp]# vim case.sh

#/bin/bash
read -p "Please input a number: " n
m=$[$n%2]
echo $m
case $m in
        1)
                echo "The number is jishu."
                ;;
        0)
                echo " The number is oushu."
                ;;
        *)
                echo "It is not jishu or oushu."
                ;;
esac

[[email protected] tmp]# sh case.sh

Please input a number: 12

0

 The number is oushu.

[[email protected] tmp]# sh case.sh

Please input a number: 11

1

The number is jishu.

[[email protected] tmp]# sh case.sh

Please input a number: abcdef

0

 The number is oushu.

for用法

sed的使用

[[email protected] tmp]# seq 1 10

1

2

3

4

5

6

7

8

9

10

[[email protected] tmp]# seq 1 2 10

1

3

5

7

9

[[email protected] tmp]# seq 10 -2 1

10

8

6

4

2

[[email protected] tmp]# seq -w 1 10

01

02

03

04

05

06

07

08

09

10

[[email protected] tmp]# vim for.sh

#/bin/bash
for i in `seq 1 10`;
do
        echo $i
done

[[email protected] tmp]# sh for.sh

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