Hold or delete message files containing specific substrings in their envelope From: address, Subject: line, or content. By default, message files are held (/HOLD). Specify /DELETE to instead delete matching message files. The /CONTENT, /ENV_FROM, and /SUBJECT qualifiers are used to specify the substrings for which to search. Any combination of /CONTENT, /ENV_FROM, and /SUBJECT may be specified. However, only one of each may be used. The /MATCH qualifier controls whether a message file must contain all (/MATCH=AND, the default) or only one of (/MATCH=OR) the specified substrings in order to be held or deleted. The default is /MATCH=AND. By default, each substring to be searched for must be at least 24 bytes long (/MIN_LENGTH=24). This is a safety measure: the longer the substring, the less likely the chance of false "hits". Use the /MIN_LENGTH qualifier to override this limit. Also by default, only message files identified by the queue cache database are searched (/DATABASE). Use the /DIRECTORY_TREE qualifier to instead search all message files actually present in the channel queue directory tree. The optional channel parameter restricts the search to message files in the specified channel. The channel parameter may use * and ? wild cards. The /THREADS qualifier may be used to accelerate searching on multiprocessor systems by dividing the work amongst multiple, simultaneously running threads. To run n simultaneous searchingg threads, specify /THREADS=n. The value n must be in the range 1-8. The default is /NOTHREADS.