OS X (Apple)

#!/bin/csh -f
 
if ($#argv < 1) then
        echo
        echo "Usage: checkseq <name> "
        echo
        exit -1
endif
@ max = 0
@ min = 999999
foreach i ( `\ls ./$1*.dpx` )
        set nohead = $i:t
        set no_dpx_ext = $nohead:r
        @ current_count = $no_dpx_ext:e
        if ($max < $current_count) then
                @ max = $current_count
        endif
        if ($min > $current_count) then
                @ min = $current_count
        endif
end
@ count = $min
loop:
        if (!(-e $1.$count.dpx)) then
                echo "File $1.$count.dpx ALERT IMAGE MISSING"
        endif
        @ count++
        if ($count > $max) then
                echo ""
                echo ""
                echo "  First image in sequence: $min"
                echo "   Last image in sequence: $max"
                echo ""
                echo "  Unless specified, all images "
                echo "  between $min and $max are present."
                echo ""
                exit 1
        else
                goto loop
        endif

#!/bin/bash

MAX=0   MIN=999999      TOTAL=0

# Don't have functions in csh.  Can't redirect to stderr properly either.
function die    # Print an error message to stderr, return 1
{
        echo "$@" >&2   ;       exit 1
}

[ "$#" -ne 1 ] && die "Usage: $0 <prefix>"      # Die unless exactly 1 arg

# Loop over all files.  (NOTE: May exceed argmax in other shells)
for I in ${1}.[0-9][0-9][0-9][0-9][0-9].dpx
do
        [ -f "$I" ] || die "No files found for prefix $1"
        # csh doesn't have a proper 'read'.  You can read from your TTY, that's it
        IFS="." read G C G <<< "$I"     # Extract number from string

        # Strip all leading zeroes
        while [ "${C:0:1}" == "0" ] && [ ! -z "${C:1:1}" ]
        do
                C="${C##0}"
        done

        [ "$C" -gt "$MAX" ] && MAX=$C   # Update max
        [ "$C" -lt "$MIN" ] && MIN=$C   # Update min
        ((TOTAL++))
done

for ((N=MIN; N<=MAX; N++))
do
        FILE=$(printf "%s.%05d.%s" "$1" $N "dpx")

        [ -f "$FILE" ] || echo "$FILE missing" >&2
done

[ "$TOTAL" -lt "$(((MAX-MIN)+1))" ] &&
        die "$((((MAX-MIN-TOTAL)+1))) files missing"

printf "No files missing in %s.%05d.dpx - %s.%05d.dpx\n" $1 $MIN $1 $MAX >&2

exit 0