eas@turing.acs.virginia.edu (Edward A. Schwab) (06/18/91)
Help! I'm trying to run a simple csh shell file that sets $OUT.out to an output filename and $PROG to a program name, will search for $OUT.out, and delete it... I'm trying to do an "if ( -e $OUT.out ) set x=$<", which will wait for an ENTER before continuing with the program... The only thing is that the "if ( -e )" statement (that searches for the existance of the file) runs if there is an actual $OUT.out file or not... **sigh** How can I make this wait for an enter keypress ONLY if $OUT.out exists??? All of the other if -e's work (the echos and the rm...) BTW, the actual executable is called .$PROG; this is called up by $PROG... :) I hope this message makes SOME sense when you look at the actual shell script below: ----------------------------------------------------------------------------- #!/bin/csh setenv OUT for005 setenv PROG asymtc1 if ( -e $OUT.out ) clear if ( -e $OUT.out ) echo '******************************************************' if ( -e $OUT.out ) echo 'You have a leftover '$OUT'.out file. Since '$PROG'' if ( -e $OUT.out ) echo 'will end up choking on this leftover file, I am going' if ( -e $OUT.out ) echo 'to delete it for you. If you do not want me to' if ( -e $OUT.out ) echo 'delete it, hit ^C, ENTER, and rename it to a different' if ( -e $OUT.out ) echo ' filename.' if ( -e $OUT.out ) echo '******************************************************' if ( -e $OUT.out ) echo ' ' if ( -e $OUT.out ) echo ' If you want it deleted, press ENTER now to continue.' if ( -e $OUT.out ) set x=$< if ( -e $OUT.out ) rm $OUT.out .$PROG echo 'Now filtering...' mv $OUT.out $OUT.asa asa $OUT.asa >$OUT.out rm $OUT.asa echo ' ' echo 'Done! File written to '$OUT.out'.' echo ' ' ------------------------------------------------------------------------------- Thanks, - Ed (eas@turing.acs.virginia.edu) (eschwab@polaris.cv.nrao.edu)
jik@cats.ucsc.edu (Jonathan I. Kamens) (06/18/91)
In article <1991Jun17.195519.12713@murdoch.acc.Virginia.EDU>, eas@turing.acs.virginia.edu (Edward A. Schwab) writes: |> Help! I'm trying to run a simple csh shell file that sets $OUT.out to an |> output filename and $PROG to a program name, will search for $OUT.out, and |> delete it... I'm trying to do an "if ( -e $OUT.out ) set x=$<", which will |> wait for an ENTER before continuing with the program... The only thing is |> that the "if ( -e )" statement (that searches for the existance of the file) |> runs if there is an actual $OUT.out file or not... In order to realize why this is happening, you have to keep in mind exactly what $< is. In particular, it's a gross hack to do keyboard input using a variable substitution. *Variable substition* is the key here. On a single line "if" statement in C-shell input, variable substitution happens on the entire line *before* the boolean of the "if" statement is checked. Since the $< hack is a variable substitution, the shell reads a line of input in order to put a value in place of $< *before* it checks if the boolean is true. The fix is simple. Change your script to read: if ( -e $OUT.out) then set x=$< endif In fact, a large portion of your script can be enclosed in that if statement. Rather than checking if $OUT.out exists before each line of the warning is printed, you can do: if ( -e $OUT.out ) then clear echo '******************************************************' echo 'You have a leftover '$OUT'.out file. Since '$PROG'' echo 'will end up choking on this leftover file, I am going' echo 'to delete it for you. If you do not want me to' echo 'delete it, hit ^C, ENTER, and rename it to a different' echo ' filename.' echo '******************************************************' echo ' ' echo ' If you want it deleted, press ENTER now to continue.' set x=$< rm $OUT.out endif -- Jonathan Kamens jik@CATS.UCSC.EDU
tchrist@convex.COM (Tom Christiansen) (06/18/91)
From the keyboard of eas@turing.acs.virginia.edu (Edward A. Schwab):
:Help! I'm trying to run a simple csh shell file that sets $OUT.out to an
:output filename and $PROG to a program name, will search for $OUT.out, and
:delete it... I'm trying to do an "if ( -e $OUT.out ) set x=$<", which will
:wait for an ENTER before continuing with the program... The only thing is
:that the "if ( -e )" statement (that searches for the existance of the file)
:runs if there is an actual $OUT.out file or not... **sigh** How can I make
:this wait for an enter keypress ONLY if $OUT.out exists??? All of the other
:if -e's work (the echos and the rm...) BTW, the actual executable is called
:.$PROG; this is called up by $PROG... :)
you need to say
if (-e foo) then
set x = "$<"
endif
so it doesn't try to eval the $< even when it doesn't need to.
:
:I hope this message makes SOME sense when you look at the actual shell script
:below:
:-----------------------------------------------------------------------------
:#!/bin/csh
you forgot the -f.
:setenv OUT for005
:setenv PROG asymtc1
now you have a WHOLE LOT of -e's. why don't you just do one and make
a block and save a lot of stat's, plus the $< headache?
there's nothing in this script demanding csh. why don't you do yourself
a favor and use sh? it sure beats a boot to the head, which is all
csh will ever give you.
--tom
--
Tom Christiansen tchrist@convex.com convex!tchrist
"So much mail, so little time." muquit@garfield.ncat.edu (MUHAMMAD A. MUQUIT) (06/19/91)
In article <1991Jun17.195519.12713@murdoch.acc.Virginia.EDU> Edward Schwab writes: >Help! I'm trying to run a simple csh shell file that sets $OUT.out to an >output filename and $PROG to a program name, will search for $OUT.out, and >delete it... I'm trying to do an "if ( -e $OUT.out ) set x=$<", which will >wait for an ENTER before continuing with the program... The only thing is >that the "if ( -e )" statement (that searches for the existance of the file) >runs if there is an actual $OUT.out file or not... **sigh** How can I make >this wait for an enter keypress ONLY if $OUT.out exists??? All of the other >if -e's work (the echos and the rm...) BTW, the actual executable is called >.$PROG; this is called up by $PROG... :) > >I hope this message makes SOME sense when you look at the actual shell script >below: >----------------------------------------------------------------------------- >#!/bin/csh >setenv OUT for005 >setenv PROG asymtc1 >if ( -e $OUT.out ) clear >if ( -e $OUT.out ) echo '******************************************************' >if ( -e $OUT.out ) echo 'You have a leftover '$OUT'.out file. Since '$PROG'' >if ( -e $OUT.out ) echo 'will end up choking on this leftover file, I am going' >if ( -e $OUT.out ) echo 'to delete it for you. If you do not want me to' >if ( -e $OUT.out ) echo 'delete it, hit ^C, ENTER, and rename it to a different' >if ( -e $OUT.out ) echo ' filename.' >if ( -e $OUT.out ) echo '******************************************************' >if ( -e $OUT.out ) echo ' ' >if ( -e $OUT.out ) echo ' If you want it deleted, press ENTER now to continue.' >if ( -e $OUT.out ) set x=$< >if ( -e $OUT.out ) rm $OUT.out >.$PROG >echo 'Now filtering...' >mv $OUT.out $OUT.asa >asa $OUT.asa >$OUT.out >rm $OUT.asa >echo ' ' >echo 'Done! File written to '$OUT.out'.' >echo ' ' >------------------------------------------------------------------------------- > > Thanks, > - Ed (eas@turing.acs.virginia.edu) > (eschwab@polaris.cv.nrao.edu) What about this? ----------------------------------------- #!/bin/csh setenv OUT for005 setenv PROG asymtc1 if ( -e $OUT.out ) then echo -n "continue [y]?" set x=$< if ( $x != n ) then echo "Things you want to do here" endif else echo "file does not exist, exiting shell" endif ------------------------------------------ is this what you want? Thanks. - - :+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+: : Muhammad A. Muquit Office: 126 Graham Hall : : Graduate Student Phone: (919) 334-7737 ext 53 : : Dept. of Civil Engineering e-mail: muquit@garfield.ncat.edu : : North Carolina A&T State University or, muquit@vanity.ncat.edu : : Greensboro, NC 27411 : :+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+:+: --