Shell Programming and Scripting

A general test without file exists checks to see if there are still glob characters in the filename, which should also work, but also only if there are no file names with actual glob characters:

Code:

for i in N???
do 
  if [ "${i%[?*]*}" = "$i" ]; then
    printf "%\n" "$i"
  done
done

or

Code:

for i in N???
do 
    case $i in (*[?*]*)
      break
    esac
    printf "%\n" "$i"
done

I think in ksh it is

set -o noglob

The disadvantage of this (and of bash's nullglob) is that the option is turned on until you turn it off explicitly. I suggest that you switch to zsh, where you can define this behaviour for each pattern separately. In zsh, the loop would be written as

Code:

    for fn in N???(N)
    do
        ....
    done

and the body would be skipped if there is no file matching the pattern; no error message here. While zsh differs in several ways from ksh/bash/dash, I find it much more convenient for shell programming than the other ones.

Just checked on zsh, thanks. I will keep this shell in mind

No. set -o noglob is a synonym for set -f in ksh. Both of which disable globing; they are not equivalent to the bash shopt -s nullglob.

If a directory contains files named x.txt and y.txt, the commands:

Code:

set +f	# default initial state
for i in *.txt
do	printf '%s\n' "$i"
done

produces the output:

Code:

x.txt
y.txt

and the commands:

Code:

set -f	# turn off globing
for i in *.txt
do	printf '%s\n' "$i"
done

produces the output:

Code:

*.txt

The set -f and set +f commands are required by the standards and are available in bash, ksh, and zsh.