Question

I have next code with while loop in my sctipt :

TMP_FILE=`mktemp`
some_script.sh | grep aa > $TMP_FILE 
while read i
   do
      echo $i
      number=`ssh somehost cat somefile | grep 11 `  
      echo $number
   done < $TMP_FILE

Contents of TMP_FILE looks like :

hostname1 AB_CDEF_JH10
hostname2 BC_DEF_JK19
...

In this case, script works correctly only one loop pass, picking up first line from TMP_FILE. After that , script exit. Is there any idea why it do not want to process other lines except firs one ?

Answer 1

Try passing the -n option to ssh to prevent it from reading from stdin.

By default, ssh reads from stdin (which is your file, in this case) and forwards it to the stdin of the command running on the remote host. As a result, your whole file gets consumed by ssh and the loop only executes once!