NAME

     entr — run arbitrary commands when files change

SYNOPSIS

     entr [-cdpr] utility [argument ...] [/_]

DESCRIPTION

     A list of files provided on the standard input and the utility is executed using the
     supplied arguments if any of them change.  entr waits for the child process to finish before
     responding to subsequent file system events.  A TTY is also opened before entering the watch
     loop in order to support interactive utilities.

     The arguments are as follows:

     -c      Execute /usr/bin/clear before invoking the utility specified on the command line.

     -d      Track the directories of regular files provided as input and exit if a new file is
             added.  This option also enables directories to be specified explicitly.  Files with
             names beginning with ‘.’ are ignored.

     -p      Postpone the first execution of the utility until a file is modified.

     -r      Reload a persistent child process.  SIGTERM is used to terminate the utility before
             it is restarted. A process group is created to prevent shell scripts from masking
             signals.  entr waits for the utility to exit to ensure that resources such as
             sockets have been closed.

     The first occurrence of /_ on the command line will be replaced with the absolute path of
     the first file that was modified.  If the restart option is used the first file under watch
     is treated as the default.

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 exits with one of the following values:

           0       SIGINT or SIGTERM was received
           1       No regular files were provided as input or an error occurred
           2       A file was added to a directory while using the while using the directory
                   watch option

EXAMPLES

     Rebuild a project if source files change, limiting output to the first 20 lines:

           $ find src/ | entr sh -c 'make | head -n 20'

     Launch and auto-reload a node.js server:

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

     Clear the screen and run a query after the SQL script is updated:

           $ echo my.sql | entr -p psql -f /_

     Rebuild project if a source file is modified or added to the src/ directory:

           $ while sleep 1; do ls src/*.rb | entr -d rake; done