CODEWITHSUNDEEP
shellunixssh
avinashse
avinashse

Reputation: 1460

use of ssh variable in the shell script

I want to use the variables of ssh in shell script. suppose I have some variable a whose value I got inside the ssh and now I want to use that variable outside the ssh in the shell itself, how can I do this ?

ssh my_pc2 <<EOF
<.. do some operations ..>
a=$(ls -lrt | wc -l)
echo \$a
EOF
echo $a

In the above example first echo print 10 inside ssh prints 10 but second echo $a prints nothing.

Upvotes: 2

Views: 260

Answers (2)

Laurence Renshaw
Laurence Renshaw

Reputation: 652

I would refine the last answer by defining some special syntax for passing the required settings back, e.g. "#SET var=value"

We could put the commands (that we want to run within the ssh session) in a cmdFile file like this:

a=`id`
b=`pwd`
echo "#SET a='$a'"
echo "#SET b='$b'"

And the main script would look like this:

#!/bin/bash

# SSH, run the remote commands, and filter anything they passed back to us
ssh user@host <cmdFile | grep "^#SET " | sed 's/#SET //' >vars.$$

# Source the variable settings that were passed back
. vars.$$
rm -f vars.$$

# Now we have the variables set
echo "a = $a"
echo "b = $b"

If you're doing this for lots of variables, you can add a function to cmdFile, to simplify/encapsulate your special syntax for passing data back:

passvar()
{
  var=$1
  val=$2
  val=${val:-${!var}}
  echo "#SET ${var}='${val}'"
}

a=`id`
passvar a
b=`pwd`
passvar b

You might need to play with quotes when the values include whitespace.

Upvotes: 1

Unknown
Unknown

Reputation: 5772

A script like this could be used to store all the output from SSH into a variable:

#!/bin/bash

VAR=$(ssh user@host << _EOF
id
_EOF)

echo "VAR=$VAR"

it produces the output:

VAR=uid=1000(user) gid=1000(user) groups=1000(user),4(adm),10(wheel)

Upvotes: 0

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