Shell Programming and Scripting

IM-0001-0001.dcm
IM-0001-0002.dcm
IM-0001-0003.dcm
IM-0001-0004.dcm
IM-0001-0005.dcm

ls -1 *.dcm | awk -F"-" '{print $3}' > ori.txt

[]$ cat ori.txt 
0001.dcm
0002.dcm
0004.dcm
0005.dcm

[]$ cat main.txt 
0001.dcm
0002.dcm
0003.dcm
0004.dcm
0005.dcm

[]$ diff ori.txt main.txt 
2a3
> 0003.dcm

$ cat missing.awk

X=match($0, /[0-9]+\.[^.]*$/) {
        Y=match($0, /\.[^.]*$/);
        PFIX=substr($0, 0, X-1); # IM-0001-
        EXT=substr($0, Y);        # .dcm
        VAL=substr($0, X, Y-X); # 0003

        # To check if the number of digits is changing.
        DIGITS[PFIX,EXT,length(VAL)]++;

        # The +0 is to guarantee a numeric sort, not alphabetic, so "01" < "2".
        if((!SMIN[PFIX,EXT]) || (SMIN[PFIX,EXT]>(VAL+0))) SMIN[PFIX,EXT]=VAL+0;
        if((!SMAX[PFIX,EXT]) || (SMAX[PFIX,EXT]<(VAL+0))) SMAX[PFIX,EXT]=VAL+0;
        F[PFIX,EXT,VAL]=1;
}

END {
        for(X in SMAX)
        {

                split(X, A, SUBSEP);
                PFIX=A[1];      EXT=A[2];

                DC=0;
                DMAX=0;
                for(Z in DIGITS)
                {
                        split(Z, A, SUBSEP);
                        if((A[1] != PFIX) || (A[2] != EXT)) continue;
                        if(A[3] > DMAX) DMAX=A[3];
                        DC++;
                }

                if(DC == 1)     CMDSTR="%0" DMAX "d"
                else            CMDSTR="%d"

                for(N=SMIN[X]+0; N<=(SMAX[X]+0); N++)
                {
                        VAL=sprintf(CMDSTR, N);
                        if(!F[PFIX,EXT,VAL])
                                print "Missing", PFIX VAL EXT;
                }
        }
}

$ touch IM-0001-{0001..0005}.dcm file-{8..15}.dat
$ rm IM-0001-0003.dcm file-9.dat file-11.dat
$ ls | awk -f missing.awk
Missing file-9.dat
Missing file-11.dat
Missing IM-0001-0003.dcm

$

printf "%s\n" *.dcm | awk -F'[-.]' '$3>p+1{for(i=p+1;i<$3;i++){s=$0; sub($3"."$4,sprintf("%04d",i)"."$4,s); print s}}{p=$3}'