Unix Tutorials and HowTos

Question and answer for users of Unix-like operating systems. Topic includes – Unix commands, servers, security, networking, shell programming, troubleshooting and much more ( rss feed ).

I often see commands as follows posted on blog or forums

cp /etc/httpd/httpd.{,.bakup}


mv resume{z,}.doc

What is the purpose of {,} in Linux and Unix shell commands?


Recently, I switched from MS-Windows based web-server to CentOS Linux based Apache web-server. All user uploaded files are stored in /var/www/uploads/ directory. Is there command that can give me a list of files that have been added to the filesystem at /var/www/uploads/ in last 7 days on Linux/Unix-like oses?


I am a new Unix system admin. How do I find ouw who has recently use the Linux or Unix-like server? Which terminals they used, and when they logged in and out of the my server?


whereis command

I am a new Linux and Unix-like system command line user. How do I find and locate the binary, source, and manual page files for a given command?


I have four Apache backend servers in front of nginx reverse proxy server. How do I make sure nginx reverse proxy load balancer always send specific client IP address (say IP request to http://apachereadwrite/ backend and rest to http://apachereadonly/ backend?


I am a new Python user. I would like to delay execution for five seconds in a Python script. How do I add a time delay in Python on Unix/Linux? Is there a sleep command in python like the Unix/Linux sleep utility to suspend execution of a bash script?


Apache has status page that can provide data about Apache. How do I enable and display such page using nginx server? How do I enable nginx status page on Linux or Unix-like operating systems?