Commands using echo (1,545)

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands


Check These Out

Read all the S.M.A.R.T. data from a hard disk drive
This is to pull all the saved S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) information from a hard drive. This can give you an idea of the nature and extent of an issue on a failing hard drive.

Comment out a line in a file
This will comment out a line, specified by line number, in a given file.

dd if=/dev/null of=/dev/sda
removes all files/filesystems of a harddisk. It removes EVERYTHING of your hard disk. Be carefull when to select a device. It does not prompt for and second check.

Take a screenshot every 2 seconds
Take a screenshot every 2 seconds and save it as a png file

Export a subset of a database
Limits the number of rows per table to X

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Blackhole any level zones via dnsmasq
Explanation It creates dnsmasq-com-blackhole.conf file with one line to route all domains of com zones to 0.0.0.0 You might use "address=/home.lab/127.0.0.1" to point allpossiblesubdomains.home.lab to your localhost or some other IP in a cloud.

Get information about memory modules
To take information about the characteristics of the installed memory modules.

Limit the cpu usage of a process
This will limit the average amount of CPU it consumes.

Do command when logged in from certain ips using ssh
Place in ~/.bashrc If you login to a ssh server from different ips, sometimes you want to do something specific for each. e.g., quickly go into screen -x session from a phone, but not your desktop.


Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: