The following sed command will individually redact all credi…

The following sed command will individually redact all credit card numbers found on each line of the input stream. These numbers will appear in the format of most major CC numbers (e.g., sixteen digits divided into four hyphen-delimited groups of four digits each). Further, any data not matching this format should be left unmodified (i.e., no false positives are allowed). Assume sed was executed using the -E or -r switches.  

When a write to a pipe exceeds PIPE_BUF number of bytes, thi…

When a write to a pipe exceeds PIPE_BUF number of bytes, this action may be non-atomic, and thus produce unexpected and undesirable results. This is primary purpose behind which we aim to conduct all pipe I/O operations using sizes less-than-or-equal-to PIPE_BUF quantity bytes.