How To Redirect Stderr To Stdout In Linux Bash?
I have an application. This application can be run from command line. This application is a bit old and requires some optional libraries but I can not find them because of this libraries are deprecated. So when running this applications they throw errors to the command line. I will save standard output of this app but I do not want to save error or warnings. How can I redirect error logs to other file or null?
Bash Redirection Types
As we know Linux work logic sits up to file operations. So everything in Linux is file. So to access files handles are used. While running applications there is handles automatically created. This handles get numbers to identify.
- Standard input named stdin and numbered
- Standard output named stdout and numbered 1
- Standard error named stderr and numbered 2
Redirect Standard Error To A File
Standard error is a output type where application or program related logs are redirected. We can redirect this error stream into a file like below. We will redirect
ls command error into a log file named
$ls / 2> errors.log
- We redirect ls stderr with 2> to the errors.log file
Redirect Standard Error to Standard Output File
$ls / &> log.log
- Merge standard output and standard error and send log.log
Redirect Standard Error To Standard Out
$ls / 2>&1
- Merge standard output and standard error