Commands tagged heartbeat (1)

  • This command telnet and and looks for a line starting with "SSH" - works for OpenSSH since the SSH banner is something like "SSH-2.0-OpenSSH_6.0p1 Debian-4+deb7u3". Then it triggers an action accordingly. It can be packed as a script file to echo 0/1 indicating the SSH service availability: if [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]]; then echo 1; else echo 0; fi; Alternative uses: Trigger an action when server is UP (using &&): [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]] && <command when up> Trigger an action when server is DOWN (using ||): [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]] || <command when down>


    0
    $if [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]]; then <command when up>; else <command when down>; fi;
    paulera · 2016-02-02 13:06:51 3

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

Running a command at a specific time

Convert JSON to YAML
Requires installing json2yaml via npm: npm install -g json2yaml (can also pipe from stdin) Ref: https://www.npmjs.com/package/json2yaml

Count to 65535 in binary (for no apparent reason)
Yes, it's useless.

Find usb device
I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

list block devices
Shows all block devices in a tree with descruptions of what they are.

Get Dollar-Euro exchage rate
You can get others rates changing the "EUR/US" part. look at the url: wap.kitco.com/exrate.wml to get more options.

Use lynx to run repeating website actions
This command will tell lynx to read keystrokes from the specified file - which can be used in a cronjob to auto-login on websites that give you points for logging in once a day *cough cough* (which is why I used -accept_all_cookies). For creating your keystroke file, use: $ lynx -cmd_log yourfile

Install pip with Proxy
Installs pip packages defining a proxy

Display summary of git commit ids and messages for a given branch
In color. Additionally you may define in your ~/.gitconfig and run it just as 'git one': one = log --pretty='format:%Cgreen%H %Cred%ai %Creset- %s'

remove ^M characters from file using sed
removing ^M characters from file with sed


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: