Problem with unix "foreach" command

Question

Hi,
I am facing a problem with unix command "foreach". I trying to process files using unix foreach command. When running the script with 500 or 1000 files. It is running fine. But when I am trying to the script with 2000+ files. Its throwing an error "Arguments too long".
below is the syntax I am using in the script:
foreach name (*)
end
Could anybody help me on this issue.
Thanks in Advance.
Manasa.

Answer 1

UNIX/Linux systems expand wildcards onto the command line before invoking the
individual commands. In effect, the shell rewrites the command line you give
substituting the wildcard expansion. There is a limit to how long this command
line can get.
For example, suppose you have two files ("foo" and "bar") in your directory.
The line:
foreach name (*)
  echo $name
endgets rewritten to:
foreach name (foo bar)
  echo $name
endand then the shell starts interpreting your script. So if you have many, many
files, the rewritten line becomes:
foreach name (f1 f2 f3 ... f10927)
  echo $name
endso chances are the "foreach" line simply gets too long. To avoid problems do
it this way; it avoids any problems based on how many files you have:
ls | while read name
do
  echo $name
doneThis way the shell never exceeds its line length limitations because the
wildcard is never expanded.
Cheers