I am trying to redirect the bash output to a variable file name. Here is my script looks like
#!/bin/bash
for i in `cat servers`
do
if [ "$i" = "198.162.1.3" ];
then
var="apple"
fi
ssh test@$i "uname -n"
done > /tempout/uname_${var}.txt
I am getting the filename as /tempout/uname_.txt
Expected filename should be uname_apple.txt
The var variable in your code is used before the loop starts to create the output file.
If you want to output the result of the ssh command to a file whose name you construct from $var, then do this:
#!/bin/bash
while read -r server; do
if [ "$server" = "198.162.1.3" ]; then
var='apple'
else
var='unknown'
fi
ssh -n "test@$server" 'uname -n' >"/tempout/uname_$var.txt"
done <servers
Here, I've also changed the loop so that it reads the input file line by line (ignoring leading and trailing whitespace on each line), and I've made var get the value unknown if the if statement does not take the "true" branch.
Also, you need -n for ssh. Otherwise, ssh would consume all the available input (here redirected from the servers file).
Another change that could be made is to use case ... esac rather than an if statement, especially if the number of IP addresses that you test for is more than a couple:
#!/bin/bash
while read -r server; do
case $server in
198.162.1.3) var=apple ;;
198.162.1.5) var=cottage ;;
198.162.1.7) var=bumblebee ;;
*) var=unknown
esac
ssh -n "test@$server" 'uname -n' >"/tempout/uname_$var.txt"
done <servers
servers to be a list of IP addresses, one per line.
$IFS)
servers to be a list of IP addresses, one per line, with optional leading and trailing spaces or tabs (which will be removed / ignored).”
read -r, it's unlikely to make a big difference here as IP addresses rarely include leading or trailing whitespace. I would matter if IFS has a non-default value (like a collection of digits), in which case using IFS= (no value) in front of read becomes important.
forfor i in $(cat file)is wrong. The shell will not only do word splitting (which is the desired effect), it also does filename expansion.set -fis missing.