pipe(ADM) 19 June 1992 pipe(ADM) Name pipe - list or define pipe filesystem Syntax /etc/pipe [ -d | -l | -s pathname ] Description This utility is used to manipulate the filesystem on which anonymous pipes reside. A pipe is a first-in first-out (FIFO) data structure used to transfer the output of one program to the input of another. Pipe data structures are normally stored in the buffer cache and accessed via inodes, like regular files. The pipe data structures therefore notionally reside on a filesystem which must be mounted and both readable and write- able; otherwise pipes cannot be used. Pipes borrow inodes from this file- system, but will only write data to the physical medium under exceptional circumstances. The following options are available: -s pathname Designates the pipe filesystem to be that on which pathname resides. -d Disables pipes (there is no pipe filesystem). Currently existing pipes are not affected. -l Lists the name of the pipe filesystem (/dev/xxx). If there is no pipe filesystem, nothing is output. (This option operates by listing the names of all the block spe- cial devices in the /dev hierarchy which have the same de- vice numbers (both major and minor) as the pipe file- system.) Notes Only one pipe filesystem may be designated at a time. Changes to the pipe filesystem take effect immediately. Programs attempting to create, write to, or read from a pipe will experi- ence an error condition if no writable or readable pipe filesystem is available. Named pipes (FIFOs) reside on the filesystem containing their name, and do not use the pipe filesystem.