man mill

NAME

mill - run a command in loop

SYNOPSIS

mill [-p PERIOD|-i] [-q|-b|-B] [-M] [-T TIMEOUT] [-F FILE] [-G] [-C CONDITION] COMMAND...

DESCRIPTION

Run a shell command in loop. The command is executed in the current shell environment.
Each cycle of the loops is composed of several stages :

• record information relative to -T, -F, -G
• the COMMAND is executed
• latency stage :
  • test the condition options (-M, -T, -F, -G, -C)
  • if any is true, exit latency stage
  • wait PERIOD
  • if any condition option specified, restart latency stage
• start a new cycle

The prompt string used when the --quiet option is absent can be customized with the variables MPS1 and MPS2.
The syntax is similar to the syntax of PS1 and PS2.

The COMMAND can retrieve its own exit status returned during the last cycle with $?. The status is initialized to 0.
The CONDITION command(s) can retrieve the exit status of the current cycle execution of COMMAND with $?.

mill handles the break and continue statements, which interrupt the executed shell command :

• in the COMMAND, break will end the loop, while continue will start the latency stage
• in a CONDITION, beside the interruption of the command, break is equivalent to a zero exit status (ends the latency stage), while continue is equivalent to a non zero exit status (move on to the next condition)

OPTIONS

COMMAND : the command(s) to execute, evaluated with eval

-p, --period PERIOD : latency between two cycles, in seconds (default 0.2)

-i, --instant : don't wait between cycles (similar to -p 0); generally used with -C or other

-M, --manual : wait for the user to press [ENTER]

-T, --timeout TIMEOUT : if the time is up since the beginning of the cycle, go to the next cycle

-F, --track-file FILE : if this file was modified during the current cycle, go to the next cycle; globbing is activated (as for track --glob) and patterns are separated by |, allowing to specify multiple files within one argument

-G, --track-command-files : mill -G -- COMMAND is roughly equivalent to mill -F COMMAND -- COMMAND; all command arguments are added to the list of tracked files

-C, --condition CONDITION : if this command succeeds, go to the next cycle; this command can be used to set an arbitrary latency

-q, --quiet : output only the COMMAND output (default if session is not interactive)

-b, --unbuffered : fancy output in real time (default if any condition option specified and session is interactive)

-B, --buffered : fancy output, printed when the command execution ends (default if no condition option specified and session is interactive)

SEE ALSO

track, mmake