29 февр. 2012 г. · A simple solution is to use ifne command (if input not empty). In some distributions, it is not installed by default. It is a part of the ...

27 нояб. 2015 г. · I want to pipe the output of one command to another script. In this other script I want to check whether the input was empty or just consists of spaces.

7 февр. 2021 г. · Since the command is successful, regardless of the output, you'll have to save it in a variable and pass it to your script if it isn't empty ...

14 нояб. 2021 г. · The problem is that the data_array remains empty. On the other hand, it gets populated if I omit the pipe to the zenity command.

5 июл. 2021 г. · The answer to the question in the title, to "check if output is non-empty, and print it if it is", is to just print it unconditionally.

28 нояб. 2018 г. · Then, checking if stdin is not open on the terminal (because it is piped to a file) is done with test ! -t 0 (check if the file descriptor zero ...

17 мая 2011 г. · You could save the output in a variable, and then invoke the mail command if the length of the string is non-zero.

3 дек. 2023 г. · The correct way to check if there's anything pending on stdin would be to use select(2), but that's not directly available in a shell such as bash.

19 авг. 2024 г. · I try to create a named pipe, however, when I store data in it, it is still empty. ... A pipe is not a file; it is an inter-process communication ...

9 мар. 2016 г. · Use yes >> foo instead of yes > foo and separately :>foo to clear the file. yes >> foo cause read to open foo with O_APPEND .