how many arguments 1

[ogniemi]

simple loop:


for i in file*;do if if_no_file*;then echo "there are no files begin with file";else process file(*);done

how to check after "do" that $i is empty and then print echo "there are no files begin with file"?

[ $number_of_arguments_i -eq 0 ] && echo "there are no files begin with file" || process $i

 

[p5wizard]

how about:

numfiles=0
for i in $(ls file* 2>/dev/null)
do
(( numfiles=numfiles+1 ))
process $i
done
if (( numfiles==0 ))
then
echo no files to process
fi


HTH,

p5wizard

 

[PHV]

for i in file*; do
[ "$i" = 'file*' ] && echo "there are no files begin with file" || process $i
done


Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[columb]

Just for completeness, to avoid the extra variable, and the test on every loop you could

for i in $(ls file* 2>/dev/null || echo no files beginning with file\*)
do
  process $i
done

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Columb Healy

 

[columb]

Oops - trying to be too clever! :~/ My code snippet would only work if the 'echo no files...' were output to stderr, otherwise they get caught up in the for loop. MkII version

for i in $(ls file* 2>/dev/null || { exec >&2; echo no file\* files found; } )
do
  echo $i
done

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Columb Healy

 

[p5wizard]

exec construction is not necessary I believe:

for i in $(ls file* 2>/dev/null || echo no file\* files found; >&2 )
do
  echo $i
done

as for the extra variable - ok but... you get a free count of processed files:

numfiles=0
for i in $(ls file* 2>/dev/null)
do
 (( numfiles=numfiles+1 ))
 process $i
done
if (( numfiles==0 ))
then
 echo "no files to process"
else
 echo "${numfiles} file(s) processed"
fi

OK it wasn't asked, but I threw that one in for free ;-)

And as always, PHV's code is compact and neat.


HTH,

p5wizard

 

[columb]

p5wizard
I wasn't saying my version was best. It's a slow day and I got intreagued as to whether I could do it without the extra variable or the repetititve testing. Having done so, or rather having thought I'd done so, I couldn't resist boasting and pride came before a fall. In a real life script I would probably go for one of the simpler versions for maintainability.

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Columb Healy