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Get the return value and get the output to $results

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# 1  
Old 08-06-2014
Get the return value and get the output to $results
Code:
cmd()
{
        echo "                                                            "
        echo "$(whoami)@$(hostname):$(pwd)# $*"
        results=`eval $*`
        echo $results
 
}

I want to get the eval $* 's return value and pass it to a new variable $val, and get "eval $*" 's the output to variable $results, but I just don't want to run eval $* more than once in function "cmd" to realize this ,
Last edited by yanglei_fage; 08-06-2014 at 09:23 AM..
# 2  
Old 08-06-2014
Not clear. What do you want to achieve by eval $*? Where do you assign anything to "$val"? And how do you expect that snippet to run several times?
# 3  
Old 08-06-2014
Quote:
Originally Posted by RudiC
Not clear. What do you want to achieve by eval $*? Where do you assign anything to "$val"? And how do you expect that snippet to run several times?

I want to get the eval $* 's return value and pass it to a new variable $val, and get "eval $*" 's the output to variable $results, but I just don't want to run eval $* more than once in function "cmd" to realize this ,
Last edited by yanglei_fage; 08-06-2014 at 09:25 AM..
# 4  
Old 08-06-2014
Code:
results=$("$@")
val=$?

# 5  
Old 08-06-2014
Quote:
Originally Posted by yanglei_fage
I want to get the eval $* 's return value
Your explanation is circular.

"What do you hope to achieve with eval $*?" "I hope to execute eval $*"


WHY do you want to execute eval $*? What chain of logic led you here? What problem led you here?

This is extremely ill-advised in nearly all circumstances. If you ever find yourself doing things like eval $* you can be fairly sure your programming took a wrong turn somewhere.
# 6  
Old 08-07-2014
Quote:
Originally Posted by neutronscott
Code:
results=$("$@")
val=$?

thanks, but it's output looks mess, how can I handle it ?
Code:
lyang001@lyang001-OptiPlex-9010:/tmp$ cat yy.sh 

results=$("$@")
val=$?
echo $results
echo $val
lyang001@lyang001-OptiPlex-9010:/tmp$ ./yy.sh ifconfig eth5
eth5: error fetching interface information: Device not found

1
lyang001@lyang001-OptiPlex-9010:/tmp$ ./yy.sh ifconfig eth0
eth0 Link encap:Ethernet HWaddr 90:b1:1c:8c:10:b7 inet addr:128.224.162.171 Bcast:128.224.163.255 Mask:255.255.254.0 inet6 addr: fe80::92b1:1cff:fe8c:10b7/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:14425536 errors:0 dropped:0 overruns:0 frame:0 TX packets:6596884 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3647161381 (3.6 GB) TX bytes:2084953656 (2.0 GB) Interrupt:20 Memory:f7f00000-f7f20000
0

---------- Post updated at 08:18 PM ---------- Previous update was at 08:16 PM ----------

Quote:
Originally Posted by Corona688
Your explanation is circular.

"What do you hope to achieve with eval $*?" "I hope to execute eval $*"


WHY do you want to execute eval $*? What chain of logic led you here? What problem led you here?

This is extremely ill-advised in nearly all circumstances. If you ever find yourself doing things like eval $* you can be fairly sure your programming took a wrong turn somewhere.
Below it's logic

val ---> is the return value of $@
results ----> is the output of $@

but the results here is mess, how can I handle it, can we use "file" to store the result or better way ?

Code:
lyang001@lyang001-OptiPlex-9010:/tmp$ cat yy.sh 

results=$("$@")
val=$?
echo $results
echo $val
lyang001@lyang001-OptiPlex-9010:/tmp$ ./yy.sh ifconfig eth5
eth5: error fetching interface information: Device not found

1
lyang001@lyang001-OptiPlex-9010:/tmp$ ./yy.sh ifconfig eth0
eth0 Link encap:Ethernet HWaddr 90:b1:1c:8c:10:b7 inet addr:128.224.162.171 Bcast:128.224.163.255 Mask:255.255.254.0 inet6 addr: fe80::92b1:1cff:fe8c:10b7/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:14425536 errors:0 dropped:0 overruns:0 frame:0 TX packets:6596884 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3647161381 (3.6 GB) TX bytes:2084953656 (2.0 GB) Interrupt:20 Memory:f7f00000-f7f20000
0

# 7  
Old 08-07-2014
I don't think the output is a mess it is just that you are passing it unquoted to echo, try:

Code:
results=$("$@")
val=$?
echo "$results"
echo $val

Last edited by Chubler_XL; 08-07-2014 at 12:54 AM..
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