function::warn - Linux
Overview
warn
is a Linux command used to display a non-fatal warning message to users. It is typically employed to alert users of potential issues or anomalies without causing an error condition or terminating the execution of a script or program.
Syntax
warn [options] message
Required Arguments
- message: The warning message to be displayed to the user.
Options/Flags
The following options are supported:
-w
: Specifies the path to a file that will store the warning message.-q
: Quiet mode. Suppresses all output except for the warning message.-h
: Displays the help message.
Examples
Simple example:
warn "Warning: File /tmp/myfile does not exist."
Write warning to a file:
warn -w /tmp/mywarnings.log "Warning: Disk space is low."
Common Issues
Exiting the script:
If a non-zero exit status is desired after displaying the warning, use the exit
command explicitly:
warn "Warning: System is overloaded."
exit 1
Unicode support:
If the warning message contains non-ASCII characters, ensure the correct locale is set or use Unicode escape sequences.
Integration
With logger
:
Log the warning message to the system log:
warn "Warning: Kernel error has occurred." | logger
With mail
:
Send the warning message as an email:
warn "Warning: Database connection failed." | mail -s "Database Alert" user@example.com
Related Commands
echo
: Displays text on the console.logger
: Logs messages to the system log.mail
: Sends electronic mail.