SUMMARY: csh Command Help

From: Lau, Victoria H (
Date: Tue Jan 09 1996 - 21:02:42 CST

Thank you so much for the quick responses. My wrapper was already
in place last night and so far I have not received any complaint
from the users. I apologize, though, for not searching through the
csh man page for more info.

My special thank you goes to the following very helpful people:

  Ken Stoddart (
  Barry Margolin (
  Matus Uhlar (
  Kevin Sheehan (Consulting Poster Child)
  Danny Johnson
  Eric Peterson (
  Mark S. Anderson (
  Tim Evans (
  Vahsen Rob (
  Peter Hesse (
and others whom I may have missed.

Original question:

I want to write a wrapper for PV Wave instead of putting the line
"source /h/pvi/wave/bin/wvstart" in our global .cshrc file. The reason
for this is that /h/pvi is automounted from the server and sourcing a
file in an automounted file system generates lots of NFS activities.

I have a sample wrapper for rs1 which resides in /usr/local/bin--this
directory is set up in our search path:

  #!/bin/csh -f

  onintr -
  setenv ...
  /h/rs1/bin/rs1 $*:q

I wonder what ":q" does in the last line. Does it "Q"uit from
/usr/local/bin/rs1 or may be it puts /h/rs1/bin/rs1 in the background
(like &)?

My proposed Wave wrapper looks like this (but I'd like to start the
wave program in the background):


    onintr -
    source /h/pvi/wave/bin/wvstart

    /h/pvi/wave/bin/wave $*:q



The ':q' /h/rs1/bin/rs1 $*:q is a C-shell event modifier. The '$*'
passes all the original command-line arguments and the ':q' modifier
quotes the '$*' values preventing C-shell from making any further

Barry Margolin pointed out that "If you want to suppress the [pid] message
that [is generated by the background command], wrap the line in parentheses,
e.g., (/h/pvi/wave/bin/wave $*:q &)"

Eric Peterson alerted me on the "onintr -" which will ignore all interrupts
so I dropped this line.

Kevin Sheehan, and a few others, suggested that I should use the Bourne
shell instead, and his recommendations are:

  1) use /bin/sh - it is much smaller/faster
  2) if there is no cleanup done afterwards, use exec - no reason for
            a shell process to hang around - and several for it to go.
  3) /bin/sh has /etc/profile - so you can have that global - you can
            also make the wrapper a built-in function, which is very fast
            and cheap.

I combined most of your suggestions and is using the following "wave"
wrapper. Will use the Bourne shell on the Solaris systems.

  #!/bin/csh -f

  source /h/pvi/wave/bin/wvsetup
  exec /h/pvi/wave/bin/`basename $0` $*:q

Portion of csh man page that I received:

Variable substitution:

     The modifiers :e, :h, :q, :r, :t, and :x can be applied (see
     History Substitution), as can :gh, :gt, and :gr. If {}
     (braces) are used, then the modifiers must appear within the
     braces. The current implementation allows only one such
     modifier per expansion.

HIstory substitution:

  Word Designators
     A :' (colon) separates the event specification from the
     word designator.

     After the optional word designator, you can add a sequence
     of one or more of the following modifiers, each preceded by
     a :.
          h Remove a trailing pathname component, leaving the
          r Remove a trailing suffix of the form .xxx', leav-
               ing the basename.
          e Remove all but the suffix.
               Substitute r for l.
          t Remove all leading pathname components, leaving
               the tail.
          & Repeat the previous substitution.
          g Apply the change to the first occurrence of a
               match in each word, by prefixing the above (for
               example, g&).
          p Print the new command but do not execute it.
          q Quote the substituted words, escaping further sub-
          x Like q, but break into words at each space charac-
               ter, tab or newline.

     Unless preceded by a g, the modification is applied only to
     the first string that matches l; an error results if no
     string matches.

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