This command displays a clock on your terminal which updates the time every second. Press Ctrl-C to exit. A couple of variants: A little bit bigger text: watch -t -n1 "date +%T|figlet -f big" You can try other figlet fonts, too. Big sideways characters: watch -n 1 -t '/usr/games/banner -w 30 $(date +%M:%S)' This requires a particular version of banner and a 40-line terminal or you can adjust the width ("30" here). Show Sample Output

Just a simple way without the need of additional tools. Of course, replace eth0 with your IF. Show Sample Output

top accecpts a comma separated list of PIDs.

This will allow you to watch as matches occur in real-time. To filter out only ACCEPT, DROP, LOG..etc, then run the following command: watch 'iptables -nvL | grep -v "0 0" && grep "ACCEPT"' The -v is used to do an inverted filter. ie. NOT "0 0"

Show active calls as the happen on an Asterisk server. Note that the Asterisk command (in single quotes) is formatted for Asterisk 1.6. Use the -n flag on the watch command to modify the refresh period (in seconds - default is 2 seconds). Show Sample Output

Shows updated status in a terminal window for connections to port '80' in a human-friendly form. Use 'watch -n1' to update every second, and 'watch -d' to highlight changes between updates. If you wish for status updates on a port other than '80', always remember to put a space afterwards so that ":80" will not match ":8080". Show Sample Output

You will see it on the corner of your running terminal. Show Sample Output

to omit "grep -v", put some brackets around a single character

This command finds the 5 (-n5) most frequently updated logs in /var/log, and then does a multifile tail follow of those log files. Alternately, you can do this to follow a specific list of log files: sudo tail -n0 -f /var/log/{messages,secure,cron,cups/error_log} Show Sample Output

Shows all those processes; useful when building some massively forking script that could lead to zombies when you don't have your waitpid()'s done just right.

Shows a simple clock in the console -t param removes the watch header Ctrl-c to exit Show Sample Output

pgrep foo may return several pids for process foobar footy01 etc. like this: 11427 12576 12577 sed puts "-p " in front and we pass a list to top: top -p 11427 -p 12576 -p 12577

Show a simple table with disk IO for the specified host. you monitor a LOT of different thing. Mostly used for MRTG and similar, but this is nice for a quick look, which disk is busy. "public" is your SNMP community ensure that snmpd is running on the host which you intend to monitor Show Sample Output

Watches the headers of a curl, following any redirects and printing only the HTTP status and the location of the possible redirects. Show Sample Output

Like command 10870, but no need for sed

This handles when you have a single call or channel. Other commands will strip out the result if there is a single channel or call active because the output changes the noun to be singular instead of plural. Show Sample Output

Sometimes top/htop don't give the fine-grained detail on memory usage you might need. Sum up the exact memory types you want

If you need to keep an eye on a command whose output is changing, use the watch command. For example, to keep an eye on your load average

To monitor .vmdk files during snapshot deletion (commit) on ESX only (ESXi doesn't have the watch command): 1. Navigate to the VM directory containing .vmdk files. # watch "ls -tough --full-time *.vmdk" where: -t sorts by modification time -o do not list group information (to narrow the output) -u sorts by access time -g only here for the purpose to easily remember the created mnemonic word 'tough' -h prints sizes in human readable format (e.g., 1K 234M 2G) --full-time sets the time style to full-iso and does not list user information (to narrow the output) optionally useful parameters to the watch command: -d highlight changes between updates -n seconds to wait between updates (default is 2) -t turn off printing the header

Note: 1) -n option of watch accepts seconds 2) -t option of notify-send accepts milliseconds 3) All quotes stated in the given example are required if notification message is more than a word. 4) I couldn't get this to run in background (use of & at the end fails). Any suggestions/improvements welcome.

A shorter version Show Sample Output

In this case it runs the command 'curl localhost:3000/site/sha' waiting the amount of time in sleep, ie: 1 second between runs, appending each run to the console. This works well for any command where the output is less than your line width This is unlike watch, because watch always clears the display. Show Sample Output