topic Re: eval command help... in Operating System - HP-UX

eval command help...

sekar sundaram — Sun, 11 Sep 2011 14:26:23 GMT

/opt/OV/bin/OpC/install/opc_ip_addr -help

Usage: opc_ip_addr [hostname] .. [hostname]
opc_ip_addr [ip] .. [ip]
opc_ip_addr -r [hexip] .. [hexip]
Convert an hostnames or an ip-adresses to a hex-ip-strings w/o dots

i want to convert a hexip to node name.

that is

opc_ip_addr -r hexip

when i run straight forward:

sekar@OVO> /opt/OV/bin/OpC/install/opc_ip_addr -r <hexip>

node.name.com = 1.1.2.3 = <hexip>

but thru a script, i will have the hexip thru a variable.

inside the script, when i run

/opt/OV/bin/OpC/install/opc_ip_addr -r $HEXIP_VARIABLE
its not using the value of HEXIP_VARIABLE. it says "no hex_ip or wrong format"

any clues?? you need more infromation??

Re: eval command help...

sekar sundaram — Sun, 11 Sep 2011 14:34:49 GMT

i got it....the $HEX_VARIABLE has a carriage return(enter key)...
any idea how to remove the "enter key" ???

Re: eval command help...

sekar sundaram — Sun, 11 Sep 2011 14:43:05 GMT

assume the value of ID is f375e6da-b5e7-71a0-0235-031f8e1e0000

now
hexvalue=cut -c26-32 $ID

this returns "-c26-32 not found

hexvalue=`cut -c26-32 $ID`
this returns
cut: Cannot open f375e6da-b5e7-71a0-0235-031f8e1e0000.

Re: eval command help...

Dennis Handly — Sun, 11 Sep 2011 14:52:40 GMT

>any idea how to remove the CR?

You fix your data file so it doesn't end in CR/LF with dos2ux(1).

Or you would remove the last char of the variable:

HEX_VARIABLE=${HEX_VARIABLE%.}

Or use echo and tr(1) to delete it.

Or use echo and cut(1) to remove it:

hexvalue=$(echo $ID | cut -c26-32)

Re: eval command help...

James R. Ferguson — Sun, 11 Sep 2011 14:56:55 GMT

Hi:

@sekar sundaram wrote:
i got it....the $HEX_VARIABLE has a carriage return(enter key)...
any idea how to remove the "enter key" ???

You could do:

HEX_VARIABLE=$(echo ${HEX_VARIABLE}|perl -pe 's/\r//g')

or even faster:

HEX_VARIABLE=$(echo ${HEX_VARIABLE}|tr -d "\015")

Regards!

...JRF...

Re: eval command help...

sekar sundaram — Sun, 11 Sep 2011 15:01:52 GMT

Cool....its good...

HEX_IP=$(echo $ID | cut -c26-32)

one more issue....

when i run

opc_ip_addr -r $HEX_IP

it runs good...

but when i assign the value to NODE like this,

NODE=opc_ip_addr -r $HEX_IP

it gives:

./script.sh: -r: not found

any ideas???

Re: eval command help...

Dennis Handly — Sun, 11 Sep 2011 15:07:19 GMT

>but when I assign the value to NODE like this: NODE=opc_ip_addr -r $HEX_IP

The correct form for command substitution is:

NODE=$(opc_ip_addr -r $HEX_IP)

>./script.sh: -r: not found

Your syntax did something like: (export NODE=opc_ip_addr; -r $HEX_IP)

Re: eval command help...

James R. Ferguson — Sun, 11 Sep 2011 15:06:10 GMT

@sekar sundaram wrote:
Cool....its good...
HEX_IP=$(echo $ID | cut -c26-32)

one more issue....

when i run
opc_ip_addr -r $HEX_IP
it runs good...

but when i assign the value to NODE like this,
NODE=opc_ip_addr -r $HEX_IP
it gives:
./script.sh: -r: not found

any ideas???

Hi:

Of course. Do:

NODE=$(opc_ip_addr -r $HEX_IP)

By the way, using 'cut' with columns means that this only works if your input string has exactly the format you want. I'd use the 'tr' I suggested above.

Regards!

...JRF...

Re: eval command help...

sekar sundaram — Sun, 11 Sep 2011 15:08:24 GMT

super cool....i got it 100%...

between,
NODE=opc_ip_addr -r $HEX_IP
for this situation, cant we use eval command?

Re: eval command help...

James R. Ferguson — Sun, 11 Sep 2011 15:11:59 GMT

@sekar sundaram wrote:
super cool....i got it 100%...

between,
NODE=opc_ip_addr -r $HEX_IP
for this situation, cant we use eval command?

Why? The $(...) for is the modern replacement for the archaic backtick syntax. This runs the command and assigns the output (if any) to the lvalue (variable).

An 'eval' is used in situations where you need the shell to scan input twice; once to interpolate variables and the second time to use them.

Regards!

...JRF...

Re: eval command help...

Dennis Handly — Sun, 11 Sep 2011 15:13:27 GMT

>for this situation, can't we use eval command?

Why? If you want to do command substitution, $() (or the archaic ``), do command substitution, not eval.