Re: input from STDIN or from a file


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Re: input from STDIN or from a file

by naikonta (Curate)

on Jan 28, 2008 at 17:16 UTC ( #664713=note: print w/replies, xml )

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in reply to input from STDIN or from a file

I don't know how complex your program would be, but I usually just use,

$ cat file.txt
a
b
c

$ cat stdin.pl
#!/usr/bin/perl -l
while (<>) {
 $_ = uc;
 print;
}

$ perl stdin.pl file.txt
A
B
C

$ cat file.txt | perl stdin.pl
A
B
C
[download]

Or, just perl -lpe '$_=uc' if it's really that simple. Anyway, I don't see anything wrong with your code.

Update: Fixed missing -l (only the dash was there). Thanks almut :-)

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Re^2: input from STDIN or from a file
by almut (Canon) on Jan 28, 2008 at 19:17 UTC

#!/usr/bin/perl -
                ^
[download]

I'm not sure you want the dash at the end of the shebang line...

It doesn't do any harm when invoking the code like you did, but when I try to run your sample code/data without explicitly calling perl (rather letting the OS handle the shebang), I'm getting

$ cat file.txt | ./664708.pl
Can't locate object method "a" via package "b" (perhaps you forgot to 
+load "b"?) at - line 1.
[download]

I suppose this is because what comes in through stdin is being interpreted as Perl code, rather than as content to be read via <> ...

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