Q. I need to run a program called oraMon.pl. However this program is run from cron job. It report error to stderr and normal output to stdout. How do I save stdout, stderr and both into 3 separate log files?

A. It is not that hard if you know howto redirect stderr, stdout and small command called tee.

=> fd0 is stdin
=> fd1 is stdout
=> fd2 is stderr

There are two formats for redirecting standard output and standard error:
&>word
and
>&word

For example anything written to fd2 to the same place as output to fd1, you will use:
2>&1

tee command read from standard input and write to standard output and file.

So to send stderr to /tmp/errors.log, stdout to /tmp/output.log and both to /tmp/final.log, type as follows:
((/path/to/oraMon.pl 2>&1 1>&3 | tee /tmp/errors.log) 3>&1 1>&2 | tee /tmp/output.log) > /tmp/final.log 2>&1

Read bash man page and tee command for more information.


🐧 Get the latest tutorials on Linux, Open Source & DevOps via RSS feed or Weekly email newsletter.

🐧 0 comments... add one


CategoryList of Unix and Linux commands
Disk space analyzersdf duf ncdu pydf
File Managementcat cp mkdir tree
FirewallAlpine Awall CentOS 8 OpenSUSE RHEL 8 Ubuntu 16.04 Ubuntu 18.04 Ubuntu 20.04
Modern utilitiesbat exa
Network UtilitiesNetHogs dig host ip nmap
OpenVPNCentOS 7 CentOS 8 Debian 10 Debian 8/9 Ubuntu 18.04 Ubuntu 20.04
Package Managerapk apt
Processes Managementbg chroot cron disown fg glances gtop jobs killall kill pidof pstree pwdx time vtop
Searchingag grep whereis which
User Informationgroups id lastcomm last lid/libuser-lid logname members users whoami who w
WireGuard VPNAlpine CentOS 8 Debian 10 Firewall Ubuntu 20.04
0 comments… add one

Leave a Reply

Your email address will not be published.

Use HTML <pre>...</pre> for code samples. Still have questions? Post it on our forum