Unique value generation in a pipe delimited file

Shell Programming and Scripting
1

I have a pipe delimited file (|) with 3 columns

Already i have values for 21000 records.

Eg:-

A|B|C
      EUFG|22|234
       SDFG|34|345

Now i have to replace the first column A values with unique values without affecting column B and C

for all the 21000 records i need to change the values (unique and can be random also)

Please help

2

Not clear.
1) Does the entire field 1 consist of one char "A" or is it a string containing "A" someplace?
2) Replacement: alphabetical or numerical or alnum allowed? How many digits/chars?

3

I guess you could use the line number for that:

awk 'NR>1{$1=NR}1' FS=\| OFS=\| file