（问题已解决）if语句的语法规则

baoersc

1. [baoer@localhost Ex_8.07-8.23]$ cat -n 0817
   
2.      1  #!/bin/bash
   
3.      2  #scriptname: idcheck
   
4.      3  #purpose: check user ID to see if user is root.
   
5.      4  #Only root has a uid of 0.
   
6.      5  #Format for id output:uid9496(ellie) gid=40 groups=40
   
7.      6  #root's uid=0.
   
8.      7  id=`id | awk -F '[=c]' '{print $2}'` # Get user ID
   
9.      8  echo your user id is: $id
   
10.      9  if [ $id -eq 0 ]
    
11.     10  then
    
12.     11          echo "you are superuser."
    
13.     12  else
    
14.     13          echo "you are not superuser."
    
15.     14  fi
    
16.     15
    
17. [baoer@localhost Ex_8.07-8.23]$ sh ./0817
    
18. your user id is: 500(baoer) gid
    
19. ./0817: line 9: [: too many arguments
    
20. you are not superuser.
    
21. [baoer@localhost Ex_8.07-8.23]$ sh ./0817 > 2>&1
    
22. -bash: syntax error near unexpected token `2'
    
23. [baoer@localhost Ex_8.07-8.23]$ sh ./0817
    
24. your user id is: 500(baoer) gid
    
25. ./0817: line 9: [: too many arguments
    
26. you are not superuser.
    
27. [baoer@localhost Ex_8.07-8.23]$ uname -a
    
28. Linux localhost.localdomain 2.6.32-431.el6.i686 #1 SMP Fri Nov 22 00:26:36 UTC 2013 i686 i686 i386 GNU/Linux
    
29. [baoer@localhost Ex_8.07-8.23]$
    

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if表达式还有其他语法规定，第九行提示参数太多，结果又能运行？请DX明示

absnm

     1  #!/bin/bash
     2  #scriptname: idcheck
     3  #purpose: check user ID to see if user is root.
     4  #Only root has a uid of 0.
     5  #Format for id output:uid9496(ellie) gid=40 groups=40
     6  #root's uid=0.
     7  #id=`id | awk -F '[=c]' '{print $2}'` # Get user ID
     8  echo your user id is: $UID
     9  if [ $UID -eq 0 ]
    10  then
    11          echo "you are superuser."
    12  else
    13          echo "you are not superuser."
    14  fi

Buring__

id=`id | awk -F '[=(]' '{print $2}'`

chengchow

1. id=`id | sed -r 's/.*uid=([0-9]+).*/\1/g'`
2. if [[  "$id" -eq 0 ]]; then

reyleon

因为 你的 $id 的值不是整型..

你这种要想不报语法错误.

if [ "$id" = 0 ] ;then
    ....
fi

baoersc

测试未通过回复 5# reyleon


   

baoersc

直接说明是类型不匹配

1. ./0817: line 9: [: 500(baoer) gid: integer expression expected
   

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Shell_HAT

回复 7# baoersc


2楼的代码试过了没
系统环境变量$UID可以直接使用，不必大费周章自己获取。

baoersc

回复 8# Shell_HAT
谢谢DX，我自己犯错了，将字母“C”输入为括号“（”了


   

baoersc

谢谢回复 3# Buring__