27 авг. 2012 г. · You can test for a non-empty string in Bash like this: if [[ $(ls -A) ]]; then echo "there are files" else echo "no files found" fi

8 авг. 2017 г. · I want to do this by checking if the output of the command sudo iw reg set $reg , if it is a correct input, there is no output. But if it is a wrong input, it ...

27 июн. 2018 г. · I have a command that may have an empty string as output, I want that when I execute: myCommand | something 'default' It either returns the output of myCommand ...

19 мар. 2017 г. · I want just a simple command like grep with some parameters to check if its input is empty and return the exit code. Preferably it should print the input if it ...

28 мар. 2017 г. · You can use the -q option to suppress most output, and redirect the rest of it to /dev/null . Then, the if statement can test the exit status ...

21 июн. 2017 г. · I want to check if a port is being used or not. I've used the command: netstat -an | grep <port_no> | grep -i listen. When I compare its output by running, if( ...

28 нояб. 2019 г. · I am running a command in bash. I would like to run the command only once. If the command has an output, print the output. But if there is no output, echo out ...

29 июн. 2011 г. · I want to return an exit status of 0 if the output is empty and 1 otherwise: find /this/is/a/path/ -name core.*

21 февр. 2019 г. · You could use the -z conditional expression to test if a string is empty: if [[ -z $(ls) ]]; then echo "ls returned nothing"; fi.

4 июн. 2018 г. · Just use the read command with a timeout, to see if it returns something and return some default output in cases when empty.