关于bc变量 问题求解(已解决感谢jason大神解释)

shawnloong

echo $cc
20878

bc <<<"ibase=10;obase=16;$cc"
(standard_in) 1: illegal character: ^[
(standard_in) 1: illegal character: ^[
(standard_in) 1: syntax error

$cc手工设置就不会报错求解.

jason680

回复 1# shawnloong

$ cc=20878

$ echo "ibase=10;obase=16;$cc"
ibase=10;obase=16;20878

$ echo "ibase=10;obase=16;$cc" | bc
518E

   

shawnloong

直接赋值变量没有问题的.这样就有问题了
topid=`top -c -b -n 1 |grep java | head -1 | awk '{print $1}'`
jpid=`top -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $1}'`
spid16=`echo 'ibase=10;obase=16;'$jpid''|bc`

Shell_HAT

回复 3# shawnloong


你会用双引号的呀
topid=`top -c -b -n 1 |grep java | head -1 | awk '{print $1}'`
jpid=`top -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $1}'`
spid16=`echo "ibase=10;obase=16;$jpid"|bc`

shawnloong

回复 4# Shell_HAT

又引号也有错误
     spid16=`echo "ibase=10;obase=16;$jpid"|bc`
(standard_in) 1: illegal character: ^[
(standard_in) 1: illegal character: ^[
(standard_in) 1: syntax error

Shell_HAT

回复 5# shawnloong


topid=`top -c -b -n 1 |grep java | head -1 | awk '{print $1}'`
jpid=`top -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $1}'`
echo ===$jpid===
spid16=`echo "ibase=10;obase=16;$jpid"|bc`
看看$jpid获取到的值是不是如你所愿

shawnloong

回复 6# Shell_HAT


    是的．但是bc的时候就报错了
[root@ ~]# topid=`top -c -b -n 1 |grep java | head -1 | awk '{print $1}'`
[root@ ~]# jpid=`top -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $1}'`
[root@~]# echo $jpid
26722
[root@ ~]# spid16=`echo "ibase=10;obase=16;$jpid"|bc`
(standard_in) 1: illegal character: ^[
(standard_in) 1: illegal character: ^[
(standard_in) 1: syntax error
[root@zjqs-03 ~]# echo $jpid
26722

Shell_HAT

回复 7# shawnloong


    请照抄6楼的代码，不要做任何修改。

jason680

回复 7# shawnloong

Don't forget the -b in top utility

$ top -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $0}'
1132 jenkins   20   0  675m  45m 9744 S  0.0  4.6   0:00.10 java                     

Didn't use -b argument in top utility and get data with the ANSI code/color
$ top -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $0}' | hexdump -C
00000000  1b 28 42 1b 5b 6d 20 31  31 33 32 20 6a 65 6e 6b  |.(B.[m 1132 jenk|
...

Using -b argument in top utility that get data clearly
$ top -b -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $0}'
1236 jenkins   20   0  675m  45m 9744 S  1.9  4.6  18:11.07 java                     

$ top -b -p $topid -H  -n 1 |grep java  | head -1 | awk '{print $0}' | hexdump -C
00000000  20 31 31 33 32 20 6a 65  6e 6b 69 6e 73 20 20 20  | 1132 jenkins   |
...
   

shawnloong

回复 9# jason680


    非常感谢jason大神解释，解释的很清晰，细节很重要．