Very Computer

What is the proper syntax for a 'logical or' search with grep?

I've tried two different ways with two different results!

1) grep "A \| B" file
did what I wanted

2) grep "B \| A" file
only gave matches with B

What's going on?

Thanks,

Troy

--

% grep "DVMAG \| CONV" fast.out
0 ITERATION NUMBER =  1     CONVERGENCE STATUS FLAG = -1     FNORM=  .18408D+04
0 ITERATION NUMBER =  2     CONVERGENCE STATUS FLAG = -1     FNORM=  .12396D+03
0 ITERATION NUMBER =  3     CONVERGENCE STATUS FLAG = -1     FNORM=  .84334D-03
0 CONVERGENCE STATUS FLAG =   1     CONVERGENCE HAS     BEEN ACHIEVED
0 DX .273593035498D-04 DY .582474224107D-04 DZ .298879097977D-04   DVMAG .709547803907D-04   MASS .100000000000D+04
0 ITERATION NUMBER =  1     CONVERGENCE STATUS FLAG = -1     FNORM=  .10010D+06
0 ITERATION NUMBER =  2     CONVERGENCE STATUS FLAG = -1     FNORM=  .72441D+05
0 ITERATION NUMBER =  3     CONVERGENCE STATUS FLAG = -1     FNORM=  .64016D+04
0 ITERATION NUMBER =  4     CONVERGENCE STATUS FLAG = -1     FNORM=  .29393D+03
0 ITERATION NUMBER =  5     CONVERGENCE STATUS FLAG = -1     FNORM=  .46429D+00
0 CONVERGENCE STATUS FLAG =   1     CONVERGENCE HAS     BEEN ACHIEVED
0 DX .151526323260D+00 DY-.112400484139D+00 DZ-.628783794066D-02   DVMAG .188768727233D+00   MASS .100000000000D+04
0 DX .200552713084D+00 DY-.348479148487D+00 DZ-.131365132452D+00   DVMAG .422984521797D+00   MASS .100000000000D+04
0 ITERATION NUMBER =  1     CONVERGENCE STATUS FLAG = -1     FNORM=  .11259D+08
0 ITERATION NUMBER =  2     CONVERGENCE STATUS FLAG = -1     FNORM=  .80191D+07
0 ITERATION NUMBER =  3     CONVERGENCE STATUS FLAG = -1     FNORM=  .77603D+07
0 ITERATION NUMBER =  4     CONVERGENCE STATUS FLAG = -1     FNORM=  .10634D+07
0 ITERATION NUMBER =  5     CONVERGENCE STATUS FLAG = -1     FNORM=  .29911D+06
0 ITERATION NUMBER =  6     CONVERGENCE STATUS FLAG = -1     FNORM=  .33830D+03
0 ITERATION NUMBER =  7     CONVERGENCE STATUS FLAG = -1     FNORM=  .86701D-02
0 CONVERGENCE STATUS FLAG =   1     CONVERGENCE HAS     BEEN ACHIEVED
0 DX-.180667280101D+00 DY .140636986436D+00 DZ .253990921772D-01   DVMAG .230357422143D+00   MASS .100000000000D+04
0 DX-.180667280101D+00 DY .140636986436D+00 DZ .253990921772D-01   DVMAG .230357422143D+00   MASS .100000000000D+04

% grep "CONV \| DVMAG" fast.out
0 DX .273593035498D-04 DY .582474224107D-04 DZ .298879097977D-04   DVMAG .709547803907D-04   MASS .100000000000D+04
0 DX .151526323260D+00 DY-.112400484139D+00 DZ-.628783794066D-02   DVMAG .188768727233D+00   MASS .100000000000D+04
0 DX .200552713084D+00 DY-.348479148487D+00 DZ-.131365132452D+00   DVMAG .422984521797D+00   MASS .100000000000D+04
0 DX-.180667280101D+00 DY .140636986436D+00 DZ .253990921772D-01   DVMAG .230357422143D+00   MASS .100000000000D+04
0 DX-.180667280101D+00 DY .140636986436D+00 DZ .253990921772D-01   DVMAG .230357422143D+00   MASS .100000000000D+04

% uname -a
HP-UX A.09.05 A 9000/725

% grep -V
GNU e?grep, version 1.6

[ What's the idea with the funky settings for Followups?
  I changed them back to normal.
]

: What is the proper syntax for a 'logical or' search with grep?

: I've tried two different ways with two different results!

: 1) grep "A \| B" file
: did what I wanted

: 2) grep "B \| A" file
: only gave matches with B

: What's going on?
  ^^^^^^^^^^^^^^^

You are:

i) not using 'egrep' which understands 'or's

ii) _escaping_ the or so that it _won't_ be an or!

iii) spaces matter. Too much data for me to try and figure out
     if you really want to match  'DVMAG ' or ' CONV'

: % grep "DVMAG \| CONV" fast.out

egrep 'DVMAG|CONV' fast.out

--
    Tad McClellan                          SGML Consulting
    Tag And Document Consulting            Perl programming

Quote:> iii) spaces matter. Too much data for me to try and figure out
>      if you really want to match  'DVMAG ' or ' CONV'

-p