Hide

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. 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.


If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Hide

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:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Print number of mb of free ram

Terminal - Print number of mb of free ram
free -m | awk '/buffer/ {print $4}'
2010-06-27 23:30:27
User: DaveQB
Functions: awk free
3
Print number of mb of free ram

Here we instead show a more real figure for how much free RAM you have when taking into consideration buffers that can be freed if needed.

Unix machines leave data in memory but marked it free to overwrite, so using the first line from the "free" command will mostly give you back a reading showing you are almost out of memory, but in fact you are not, as the system can free up memory as soon as it is needed.

I just noticed the free command is not on my OpenBSD box.

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives
grep '^MemFree:' /proc/meminfo | awk '{ mem=($2)/(1024) ; printf "%0.0f MB\n", mem }'
2010-06-30 18:33:29
User: dbbolton
Functions: awk grep printf
4

This will show the amount of physical RAM that is left unused by the system.

free -m | awk '/Mem/ {print $4}'

Know a better way?

If you can do better, submit your command here.

What others think

The free manpage says :

If the -o option is not specified, free subtracts buffer memory from the used memory and adds it to the free memory reported.

Unix software on unix machines are often made by smart people. Just read the man page.

Comment by CodSpirit 212 weeks and 3 days ago

CodSpirit, I like your thinking, but not having the desired effect here on a CentOS 5.3 box:

root@om012234 ~ $ free -m total used free shared buffers cached Mem: 8004 5660 2343 0 68 1639 -/+ buffers/cache: 3953 4050 Swap: 996 0 995 root@om012234 ~ $ free -mo total used free shared buffers cached Mem: 8004 5647 2356 0 68 1639 Swap: 996 0 995

3953 is the figure we are after. Omitting the -o switch gives us that.

Comment by DaveQB 193 weeks ago

Rather 4050 for RAM free. 3953 is RAM used.

Comment by DaveQB 193 weeks ago

Your point of view

You must be signed in to comment.

Related sites and podcasts