Commands by hvindin (2)

  • Run a job in the background and prefix it's output with some string. This is particularly useful if you are running inside a docker container in a startup script (sue me, I'll run two jobs in a docker container if I want to) and you can run something like: /usr/sbin/nginx 2>&1 | awk '{print "[NGINX] " $0}' & /opt/jws-3.1/tomcat8/bin/catalina.sh run 2>&1 | awk '{print "[TOMCAT] " $0}' & while true; do ; done it can also be combined with tee to create a file log as well as a stdout log, for example if the script above where a script called "/bin/start-container.sh" then you could run /bin/start-container.sh | tee /var/log/containerlogs Show Sample Output


    0
    nginx 2>&1 | awk '{print "[NGINX] " $0}' &
    hvindin · 2017-04-25 22:18:38 0
  • The example uses hashicorps packer as the sample file, but any .zip file which only contains a single file will work. Show Sample Output


    0
    curl -Ss https://releases.hashicorp.com/packer/1.0.0/packer_1.0.0_linux_amd64.zip | zcat > packer
    hvindin · 2017-04-25 22:03:11 0

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

Search for commands from the command line
Search at CommandLineFu.com from your terminal. Get the clfu-seach at http://www.colivre.coop.br/Aurium/CLFUSearch

bulk dl files based on a pattern
-O switch creates local filename same as remote curl [][] -o #1#2 makes local files unique inserting sequence values into #x placeholders sequences can be alpha or numeric e.g [a-z] [1-25]

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Lists all usernames in alphabetical order
Save some CPU, and some PIDs. :)

Get information on your graphics card on linux (such as graphics memory size)
Loop is needed if you have more then one card.

add a backup (or any other) suffix to a file
Very helpful when you've got complex filenames and needs to change just some small parts of it. Renaming a file called "i-made-a-small-typo-right-here" to "i-made-a-big-typo-right-here": $ mv -vi i-made-a-{small,big}-typo-right-here You could also copy multiple files, edit, remove, process, etc.

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

Print all the lines between 10 and 20 of a file
Subtly different to the -n+p method... and probably wrong in so many ways....... But it's shorter. Just.

Check reverse DNS
I'm just a simple programmer. I find dig too verbose. host tells me alias(es) and IP address in a quick to grok format with nothing special to remember for input parameters. With thanks to http://www.cyberciti.biz/faq/how-to-test-or-check-reverse-dns/

Recursively remove 0kb files from a directory


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: