Linux command
ifne 命令
文本
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常用示例
Run command if input
command1 | ifne command2
Delete file if results
find . -empty | ifne xargs rm
Invert condition
command | ifne -n echo "no output"
Mail if errors
make 2>&1 | ifne mail -s "errors" [admin]
说明
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.
参数
- -n
- Run if NO input.
- --help
- Display help information.
FAQ
What is the ifne command used for?
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.
How do I run a basic ifne example?
Run `command1 | ifne command2` in a terminal, then adjust file names, paths, flags, or remote targets for your system.
What does -n do in ifne?
Run if NO input.