在shell中如何判断一个数 是不是整数?如何做呢?

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在shell中如何判断一个数 是不是整数?如何做呢?

waker

1. [waker@proxy 1c]$ var=3
   
2. [waker@proxy 1c]$ [ $var -gt 0 -o $var -lt 0 ] 2>/dev/null&&echo \"$var\" is an interger||echo \"$var\" is not an interger
   
3. "3" is an interger
   
4. [waker@proxy 1c]$ var=3.5
   
5. [waker@proxy 1c]$ [ $var -gt 0 -o $var -lt 0 ] 2>/dev/null&&echo \"$var\" is an interger||echo \"$var\" is not an interger
   
6. "3.5" is not an interger
   
7. [waker@proxy 1c]$ var=-2
   
8. [waker@proxy 1c]$ [ $var -gt 0 -o $var -lt 0 ] 2>/dev/null&&echo \"$var\" is an interger||echo \"$var\" is not an interger
   
9. "-2" is an interger
   
10. [waker@proxy 1c]$ var=-2.0
    
11. [waker@proxy 1c]$ [ $var -gt 0 -o $var -lt 0 ] 2>/dev/null&&echo \"$var\" is an interger||echo \"$var\" is not an interger
    
12. "-2.0" is not an interger
    
13. [waker@proxy 1c]$ var=aa
    
14. [waker@proxy 1c]$ [ $var -gt 0 -o $var -lt 0 ] 2>/dev/null&&echo \"$var\" is an interger||echo \"$var\" is not an interger
    
15. "aa" is not an interger
    

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寂寞烈火

grep -q '^[-]\?[0-9]\+$' && echo $str is an interger || echo $str is not an interger

dearvoid

my way:

1. 
   
2. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
3. [27188 0] $ var=abc
   
4. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
5. [27188 0] $ [ -z "${var//[0-9]/}" ] && echo yes || echo no
   
6. no
   
7. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
8. [27188 0] $ var=123
   
9. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
10. [27188 0] $ [ -z "${var//[0-9]/}" ] && echo yes || echo no
    
11. yes
    
12. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
    
13. [27188 0] $ o
    

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dearvoid

如果是 bash 3.0+ 的话还可以这样:

1. 
   
2. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
3. [27188 0] $ var=123
   
4. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
5. [27188 0] $ [[ "$var" =~ [0-9]+ ]] && echo yes || echo no
   
6. yes
   
7. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
8. [27188 0] $ var=123.4
   
9. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
   
10. [27188 0] $ [[ "$var" =~ [0-9]+ ]] && echo yes || echo no
    
11. yes
    
12. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
    
13. [27188 0] $ var=hello
    
14. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
    
15. [27188 0] $ [[ "$var" =~ [0-9]+ ]] && echo yes || echo no
    
16. no
    
17. -(dearvoid@LinuxEden:tty3)-(~/tmp)-
    
18. [27188 0] $ o
    

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