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ENTR(1) General Commands Manual ENTR(1) NAME entr -- run arbitrary commands when files change SYNOPSIS entr [-acdnprsxz] utility [argument /_ ...] DESCRIPTION A list of files provided on 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: -a Respond to all events which occur while the utility is running. Without this option, entr consolidates events in order to avoid looping. This option has no effect in conjunction with the -r flag. -c Clear the screen before invoking the utility specified on the command line. Specify twice to erase the scrollback buffer. -d Track the directories of regular files provided as input and exit if a new file is added. This option also enables directo- ries to be specified explicitly. If specified twice, all new entries to a directory are recognized, otherwise files with names beginning with `.' are ignored. -n Run in non-interactive mode. In this mode entr does not at- tempt to read from the TTY or change its properties. -p Postpone the first execution of the utility until a file is modified. -r Reload a persistent child process. As with the standard mode of operation, a utility which terminates is not executed again until a file system or keyboard event is processed. 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 re- sources such as sockets have been closed. Control of the TTY is not transferred to the child process. -s Evaluate the first argument using the interpreter specified by the SHELL environment variable. -x Format custom exit status messages using a persistent awk(1) process. The path to the status script is defined by the envi- ronment variable ENTR_STATUS_SCRIPT. If the status script does not exist, entr will create an example. Shell commands and file redirection is not permitted by default, but may be en- abled by specifying -x twice. -z Exit after the utility completes. When combined with -r the utility will be restarted again only in response to commands or file system events. The first argument named /_ is replaced with the absolute path of the first file to trigger an event. The first file under watch is used as the default. If the -s option is used, the name of the first file to trigger an event can be read from $0. COMMANDS entr listens for keyboard input and responds to the following commands: <space> Execute the utility immediately. If the -r option is set this will terminate and restart the child process as if a file change event had occurred. q Quit; equivalent pressing <control-C>. ENVIRONMENT ENTR_STATUS_SCRIPT The path to the exit status script enabled by the -x op- tion. By default $HOME/.entr/status.awk is evaluated. PAGER Set to /bin/cat by default to prevent interactive utili- ties from waiting for keyboard input if output does not fit on the screen. SHELL Specify the shell to use with the -s flag. The default is /bin/sh. EV_TRACE Print file system event messages. EXIT STATUS If the -z flag is set and the utility is successfully executed, the status of the child process is returned. If the child process was ter- minated by a signal, the exit status is the signal number plus 128. entr normally returns one of the following values: 0 Normal termination after receiving SIGINT 1 No regular files were provided as input or an error oc- curred 2 A file was added to a directory and the directory watch option was specified EXAMPLES Rebuild a project if source files change, limiting output to the first 20 lines: $ find src/ | entr -s '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 -cp psql -f /_ Rebuild project if a source file is modified or added to the src/ di- rectory: $ while sleep 0.1; do ls src/*.rb | entr -d make; done Auto-reload a web server, or terminate if the server exits $ ls * | entr -rz ./httpd FreeBSD 14.3 February 6, 2025 ENTR(1)
NAME | SYNOPSIS | DESCRIPTION | COMMANDS | ENVIRONMENT | EXIT STATUS | EXAMPLES
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