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 $a prints nothing.
I would refine the last answer by defining some special syntax for passing the required settings back, e.g. "#SET var=value"
We could put the commands (that we want to run within the ssh session) in a cmdFile file like this:
a=`id`
b=`pwd`
echo "#SET a='$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.
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)
fabric (docs.fabfile.org/en/1.8) for complicated scenarios