A key option allows you to select records based in part on the data in the records

<key>

── KEY ─┬─────────────┬─<start position>─┬─ EQL ─┬──<search argument>──┤
        ├─ CHARACTER ─┤                  ├─ GTR ─┤
        ├─ BYTE ──────┤                  ├─ GEQ ─┤
        └─ DIGIT ─────┘                  ├─ LEQ ─┤
                                         ├─ LSS ─┤
                                         ├─ NEQ ─┤
                                         ├─ = ───┤
                                         ├─ > ───┤
                                         ├─ >= ──┤
                                         ├─ <= ──┤
                                         └─ < ───┘

<search argument>

──┬─ " ──<alphanumeric>── " ─┬─────────────────────────────────────────┤
  └─ @ ──<hexadecimal>── @ ──┘

Explanation

<start position>>

Identifies the starting position within a record that is used for comparison. CHARACTER is the default. BYTE is a synonym for CHARACTER. DIGIT specifies that the position is given in 4-bit digit positions. The first position in the record is position zero (0).

<search argument>>

Specifies the criterion to be used for comparison. The maximum length of the search argument is 20 bytes or 40 hex digits. A hexadecimal string must be specified if DIGIT was used to specify the <start position>. If DIGIT was not used with the <start position>, and a hexadecimal string is given as the <search argument>, the actual digit position used is twice the <start position> value (one byte = two digits).

Example 1

To select all records with the word “system” in the first 6 characters use:

KEY 0 = SYSTEM

Example 2

To select all records with a number greater than 7 in position 71 use:

KEY 71 GTR 7