ifne

ifne [options] command [args]

ifne ("if not empty") reads from standard input and runs the given command only if that input is non-empty. The buffered input is then re-emitted on the command's stdin, so the consumer sees the original stream unchanged. With -n, the behavior is inverted: the command runs only if standard input is empty (useful for handling "nothing to do" branches in scripts).This makes ifne the natural complement to filters that may produce no output: pipelines like find ... -print0 | ifne xargs -0 rm or make 2>&1 | ifne mail -s "errors" admin stay silent when there is nothing to do.

COMMAND

Command to run.

Command arguments.

Run if NO input.

Display help information.

Part of moreutils. Input must fit in memory or in the pipe buffer; the entire stream is read before the command is started, so very large inputs may be slow or memory-hungry. Stdin is only forwarded to the wrapped command when input was non-empty; in the -n case the wrapped command inherits an empty stdin.

ifne is part of moreutils, a collection of Unix tools by Joey Hess.

xargs(1), moreutils(7), test(1)