I was trying to get the date printed for the ping command is going, to simulate similar effect as in bash ping 1.1.1.1 -O | while read pong; do echo "$(date): $pong"; done, but could not make it work so far.
Tried the following on a csh shell, but does not work:
ping 1.1.1.1 -O | while ( 1 ) echo `date` end
What I am missing ? appreciate your help.
What you're missing is that the syntax used by csh and tcsh is not nearly as general and flexible as the syntax used by bash and other Bourne-derived shells.
csh does have a special-case syntax for 1-line if statements:
if (condition) statement
but it doesn't have anything similar for loops:
% while (1) echo hello
while: Expression Syntax.
and it doesn't allow piping a command's output into a loop.
If you must use csh/tcsh for some reason, you can write a script to encapsulate your while loop and pipe your command's output to that script, or you can invoke an sh or bash process to do the work for you:
csh% bash -c 'ping 1.1.1.1 -O | while read pong; do echo "$(date): $pong"; done'
(I use csh and tcsh, both interactively and for scripting, for a number of years. My own solution was first to start using bash for scripting, and then to give up on tcsh entirely and use bash as my default shell. It's a bit of a learn curve, and there are some tcsh features that aren't quite as convenient in bash, but I recommend it.)
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