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

Watch YouTube and other Flash videos via mplayer (or whatever)
Many sites with Flash video players will download video files to /tmp on Linux, with temporary filenames like "FlashbGTHm4". These will often play in mplayer, totem, or other movie playing software. You must first navigate to a video page, let it start loading, and then pause playback.

List packages manually installed with process currently running
Sometimes we install programs, we forget about them, and they stay there wasting RAM. This one-liner try to find them.

Display the output of a command from the first line until the first instance of a regular expression.
Slightly simpler version of previous sed command that does the same thing. In this case, the output will stop at the command, and the entire command will be terminated as well, instead of proceeding through the whole file.

Detect encoding of a text file
This command gives you the charset of a text file, which would be handy if you have no idea of the encoding.

Compare copies of a file with md5
I had the problem that the Md5 Sum of a file changed after copying it to my external disk. This unhandy command helped me to fix the problem.

Encrypted chat with netcat and openssl (one-liner)
client$ while true; do read -n30 ui; echo $ui |openssl enc -aes-256-ctr -a -k PaSSw ; done | nc localhost 8877 | while read so; do decoded_so=`echo "$so"| openssl enc -d -a -aes-256-ctr -k PaSSw`; echo -e "Incoming: $decoded_so"; done This will establish a simple encrypted chat with AES-256-CTR using netcat and openssl only. More info here https://nixaid.com/encrypted-chat-with-netcat/

find the biggest file in current folder

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Suppress output of loud commands you don't want to hear from
This works even if there are spaces in any word in the command line.

Join lines
awk version of 7210. Slightly longer, but expanding it to catch blank lines is easier: $ awk 'BEGIN{RS="\0"}{gsub(/\n+/,"");print}' file.txt


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: