ellard@bbn.com (Dan Ellard) (03/13/90)
I am trying to write a shell script that takes several arguments and passes them to child processes, i.e. #!/bin/csh foo $1 $2 ... bar $1 $2 ... exit 0 which I want to have the same effect as if I had typed to the shell: foo $1 $2 ... bar $1 $2 ... Unfortunately, this method does not work when $1 is something like 'a b', since $1 evaluates to the string ( a b ) without the quotes, so foo and bar think that their first argument is 'a' and their second argument is 'b', rather than that their first argument is 'a b'. My solution to this problem is to build a new argument list, "requoting" each argument, using this ugly piece of code: #!/bin/csh set count = 1 set args = $#argv set new_args = "" while ($count <= $#argv) set new_args = ( $new_args \'$argv[$count]\' ) set count = `expr $count + 1` end foo $new_args bar $new_args exit 0 (I am open to suggestions concerning how to improve this) This solves the original problem, but there are still more problems to solve-- like handling quoted characters. If I call this program with $1 as \'foo, the backslash will be peeled off and my quoting scheme will break. Similar problems will arise if I try to use other characters that have special meaning to the shell. I could get around this by writing a simple C program that re-inserts backslashes as necessary, but this seems very clumsy. Is there a good way to do this using either csh or sh, or should I give up and write a C program to do it? Thanks, Dan --------------------------------------------------------------------------- Dan Ellard -- ellard@bbn.com This line intentionally not left blank.
scott@cs.odu.edu (Scott Yelich) (03/15/90)
>I am trying to write a shell script that takes several arguments and >passes them to child processes, i.e. >#!/bin/csh >foo $1 $2 ... >bar $1 $2 ... >exit 0 >which I want to have the same effect as if I had typed to the shell: >foo $1 $2 ... >bar $1 $2 ... > Unfortunately, this method does not work when $1 is something like >'a b', since $1 evaluates to the string ( a b ) without the quotes, so >foo and bar think that their first argument is 'a' and their second >argument is 'b', rather than that their first argument is 'a b'. foo "$@" bar "$@" -- ----------------------------------------------------------------------------- Scott D. Yelich scott@cs.odu.edu [128.82.8.1] After he pushed me off the cliff, he asked me, as I fell, ``Why'd you jump?'' -----------------------------------------------------------------------------
jik@athena.mit.edu (Jonathan I. Kamens) (03/15/90)
In article <SCOTT.90Mar14212616@oswy.cs.odu.edu>, scott@cs.odu.edu (Scott Yelich) writes: > >I am trying to write a shell script that takes several arguments and > >passes them to child processes, i.e. > >#!/bin/csh > >... > > foo "$@" > bar "$@" Notice that he was talking about a *C shell* script. $@ is a *bourne shell* construct. It doesn't work in the C shell. Jonathan Kamens USnail: MIT Project Athena 11 Ashford Terrace jik@Athena.MIT.EDU Allston, MA 02134 Office: 617-253-8495 Home: 617-782-0710 P.S. Any particular reason why your signature contained almost an entire page full of blank lines?
jaap@sequent.UUCP (Jaap Vermeulen) (03/15/90)
ellard@bbn.com (Dan Ellard) writes: >I am trying to write a shell script that takes several arguments and >passes them to child processes, i.e. >#!/bin/csh >foo $1 $2 ... >bar $1 $2 ... >exit 0 >Unfortunately, this method does not work when $1 is something like 'a b', since >$1 evaluates to the string ( a b ) without the quotes, so foo and bar >(I am open to suggestions concerning how to improve this) foo $1:q $2:q bar $1:q $2:q or: foo $*:q which is equivalent to foo $@ in bourne shell >This solves the original problem, but there are still more problems to >solve-- like handling quoted characters. If I call this program with >$1 as \'foo, the backslash will be peeled off and my quoting scheme will >break. Similar problems will arise if I try to use other characters that >have special meaning to the shell. This should take care of all quoting etc. jaap. -- "Some call me Jaaper" +---------------------------+ | Sequent Computers Systems | Internet : sequent!jaap@uunet.uu.net | Beaverton, Oregon | Uucp : ...uunet!sequent!jaap +---------------------------+
iwarner@axion.bt.co.uk (Ivan Warner) (03/15/90)
In article <53408@bbn.COM>, ellard@bbn.com (Dan Ellard) writes: > I am trying to write a shell script that takes several arguments and > passes them to child processes, i.e. > > #!/bin/csh > foo $1 $2 ... > bar $1 $2 ... > exit 0 > > which I want to have the same effect as if I had typed to the shell: > foo $1 $2 ... > bar $1 $2 ... > > Unfortunately, this method does not work when $1 is something like 'a b', since > $1 evaluates to the string ( a b ) without the quotes, so foo and bar > think that their first argument is 'a' and their second argument is 'b', > rather than that their first argument is 'a b'. > > My solution to this problem is to build a new argument list, "requoting" each > argument, using this ugly piece of code: > > [UGLY code deleted] what on earth is wrong with: #!/bin/csh foo "$1" "$2" bar "$1" "$2" have I missed some subtle point, or is this not a `wizards' question
maart@cs.vu.nl (Maarten Litmaath) (03/16/90)
In article <1990Mar15.102758.17051@axion.bt.co.uk>, iwarner@axion.bt.co.uk (Ivan Warner) writes: )In article <53408@bbn.COM>, ellard@bbn.com (Dan Ellard) writes: )> I am trying to write a shell script that takes several arguments and )> passes them to child processes, i.e. )> )> #!/bin/csh )> foo $1 $2 ... )> bar $1 $2 ... )... )> Unfortunately, this method does not work when $1 is something like 'a )b', [...] )... ) what on earth is wrong with: ) )#!/bin/csh )foo "$1" "$2" )bar "$1" "$2" ) ) have I missed some subtle point, or is this not a `wizards' question You missed a subtle point: what if the number of arguments is unknown in advance? You can't say "$@" in csh. Still this isn't a wizards question, because the answer can be found in the csh manual: % set argv=('a b' \\c \') % set argv=($argv:q pp) % cat aap for i do echo "=$i=" done % sh aap $*:q =a b= =\c= ='= =pp= % -- 1) Will 4.5BSD have wait5()? |Maarten Litmaath @ VU Amsterdam: 2) Sleep(3) should be sleep(2) again.|maart@cs.vu.nl, uunet!mcsun!botter!maart
scott@cs.odu.edu (Scott Yelich) (03/16/90)
>(Scott Yelich) >writes: >>>I am trying to write a shell script that takes several arguments and >>>passes them to child processes, i.e. >>>#!/bin/csh >>>... >>foo "$@" >>bar "$@" > Notice that he was talking about a *C shell* script. > $@ is a *bourne shell* construct. It doesn't work in the C shell. Well, if I was making a shell script that JUST passed already passed values to sub shells.... I would write it in sh because there is a facility which makes this function extremely easy. See his previous message for the problems csh causes.... But, if he REALLY likes csh... perhaps? ------------------------------------------------------------------------------ eval f `repeat $#argv eval 'echo -n \"$1\"\ ; shift'` ------------------------------------------------------------------------------ However, I still prefer ``foo "$@"'' for its simplicity. > P.S. Any particular reason why your signature contained almost an entire > page full of blank lines? Did it? What about this one? Are you sure? -- ----------------------------------------------------------------------------- Scott D. Yelich scott@cs.odu.edu [128.82.8.1] After he pushed me off the cliff, he asked me, as I fell, ``Why'd you jump?'' -----------------------------------------------------------------------------
jik@athena.mit.edu (Jonathan I. Kamens) (03/16/90)
In article <SCOTT.90Mar15190447@osric.cs.odu.edu>, scott@cs.odu.edu (Scott Yelich) writes: > Well, if I was making a shell script that JUST passed already passed > values to sub shells.... I would write it in sh because there is a > facility which makes this function extremely easy. See his previous > message for the problems csh causes.... As someone else has already pointed out, there is a functionality in csh to make it extremely easy as well -- the ":q" qualifier to variable expansion (That was a feature I didn't know about, too, so thanks to whomever pointed it out!). > > P.S. Any particular reason why your signature contained almost an entire > > page full of blank lines? > > Did it? What about this one? Are you sure? You're right, it was my newsreader (xrn is brain-damaged and stupid about some things....). Jonathan Kamens USnail: MIT Project Athena 11 Ashford Terrace jik@Athena.MIT.EDU Allston, MA 02134 Office: 617-253-8495 Home: 617-782-0710
kon@mycroft.Stanford.EDU (Ronnie Kon) (03/16/90)
In article <53408@bbn.COM> ellard@BBN.COM (Dan Ellard) writes: >I am trying to write a shell script that takes several arguments and >passes them to child processes, i.e. > >#!/bin/csh >foo $1 $2 ... >bar $1 $2 ... >exit 0 > >which I want to have the same effect as if I had typed to the shell: >foo $1 $2 ... >bar $1 $2 ... > First, apologies if this is a repeat of my earlier posting...we are having some trouble with getting our postings out. It seems to me that the best way to deal with this is to put an alias in your .cshrc, on the order of alias foobar "foo \!* \; bar \!*" This will do precisely what you want, and execute a whole lot faster. If you really need a shell script, you will need to echo the arguments through sed to put backslashes before any double or back quotes appearing in them, store the result into a variable, and then double quote the resulting variable on the command lines. This is really icky. In that this is pretty easilly discernable from the manual, I would agree that it would be more at home in questions than in wizards. -- ------------------------------------------------------------------------------- Ronnie Kon | "I don't know about your brain, ronnie@mindcraft.com | but mine is really bossy" ...!{decwrl,hpda}!mindcrf!ronnie | -- Laurie Anderson -------------------------------------------------------------------------------
maart@cs.vu.nl (Maarten Litmaath) (03/17/90)
In article <SCOTT.90Mar15190447@osric.cs.odu.edu>, scott@cs.odu.edu (Scott Yelich) writes: )... )eval f `repeat $#argv eval 'echo -n \"$1\"\ ; shift'` It fails: % set argv=('a\ b c') % cat chkargs #!/bin/sh for i do echo "<$i>" done % eval chkargs `repeat $#argv eval 'echo -n \"$1\"\ ; shift'` <a b c> % What the hell is wrong with using the `:q' modifier anyway? )However, I still prefer ``foo "$@"'' for its simplicity. I prefer sh for other reasons. -- 1) Will 4.5BSD have wait5()? |Maarten Litmaath @ VU Amsterdam: 2) Sleep(3) should be sleep(2) again.|maart@cs.vu.nl, uunet!mcsun!botter!maart