You can read a specific line of a text file by entering a line number as an argument on the LINEIN method. In this example, line 3 is read from CONFIG.SYS:
/* Read and display line 3 of CONFIG.SYS */
infile=.stream~new('c:\config.sys')
say infile~linein(3)
You don't necessarily reduce file I/O by using specific line numbers. Because text files typically do not have a specific record length, REXX must read through the file counting line-end characters to find the line you want.