Commands using ssh (347)

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

statistics in one line
In this example, file contains five columns where first column is text. Variance is calculated for columns 2 - 5 by using perl module Statistics::Descriptive. There are many more statistical functions available in the module.

Multi line grep using sed and specifying open/close tags
This line does not include your closing tag in the output.

Save a file you edited in vim without the needed permissions (no echo)
Write a file you edited in Vim but that you do not have the permissions to write to (unless you use sudo.) Same as #1204 but without the echo to stdout that I find annoying.

prevent large files from being cached in memory (backups!)
We all know... $ nice -n19 for low CPU priority.   $ ionice -c3 for low I/O priority.   nocache can be useful in related scenarios, when we operate on very large files just a single time, e.g. a backup job. It advises the kernel that no caching is required for the involved files, so our current file cache is not erased, potentially decreasing performance on other, more typical file I/O, e.g. on a desktop.   http://askubuntu.com/questions/122857 https://github.com/Feh/nocache http://packages.debian.org/search?keywords=nocache http://packages.ubuntu.com/search?keywords=nocache   To undo caching of a single file in hindsight, you can do $ cachedel   To check the cache status of a file, do $ cachestats

create disk copy over the net without temp files
I wanted to create a copy of my whole laptop disk on an lvm disk of the same size. First I created the logical volume: lvcreate -L120G -nlaptop mylvms SOURCE: dd if=/dev/sda bs=16065b | netcat ip-target 1234 TARGET: nc -l -p 1234 | dd of=/dev/mapper/mylvms-laptop bs=16065b to follow its process you issue the following command in a different terminal STATS: on target in a different terminal: watch -n60 -- kill -USR1 $(pgrep dd) (see http://www.commandlinefu.com/commands/view/4356/output-stats-from-a-running-dd-command-to-see-its-progress)

list files recursively by size

diff output of two commands
This only works in bash

Backup with versioning

Symlink all files from a base directory to a target directory
Simple and easy to remember, if it already exists then it just ignores it.

Create a quick back-up copy of a file
Uses shell expansion to create a back-up called file.txt.bak


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: