NAME

     entr — run arbitrary commands when files change

SYNOPSIS

     entr [-r] utility [arguments ...]
     entr +fifo

DESCRIPTION

     entr has two modes of operation; the first use reads a list of files provided on STDIN and
     executes the supplied utility if any of them change.  entr waits for the child process to
     finish before responding to subsequent file system events. A TTY is opened before entering
     the watch loop in order to support the invocation of interactive utilities.

     -r modifies the exec mode by launching the utility at startup and reloading it if one of the
     source files change. This features requires the application to exit if it receives SIGTERM.
     entr always waits for the utility to exit to ensure that resources such as sockets have been
     closed.

     The second mode also reads a list of filenames provided on STDIN and is enabled by
     specifying '+' and the name of a fifo. In this mode entr enables more sophisticated
     scripting by writing filenames to a named pipe when they are modified.

ENVIRONMENT

     If PAGER is undefined, entr will assign /bin/cat to prevent interactive utilities from
     waiting for keyboard input if output does not fit on the screen.

EXIT STATUS

     The entr utility does not normally return, but it will exit with a value of 0 if the signal
     SIGINT or SIGTERM was received. An exit status of 1 indicates that no regular files were
     provided as input.

EXAMPLES

     Rebuild project when source files change

           $ find src | entr make

     Clear the screen and run tests

           $ ls *.py | entr sh -c 'clear; ./test.py'

     Launch and auto-reload a node.js server

           $ ls *.js | entr -r node index.js

     Convert individual Markdown files to HTML if they're modified

           $ ls *.md | entr +notify &
           $ while read F; do
           > markdown2html $F
           > done < notify

CAVEATS

     Only regular files are monitored, directories and special files are ignored.