Commands by slaamp (1)

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

List all symbolic links in current directory
Many competing commands to do this, but since most people want a Long list with Human readable files sizes and want to see All files (including hidden (.*) files) this one wins on simplicity and usefulness. Plus grep is just as, if not more portable than sed or awk, and is more widely understood. :)

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" }

grep for minus (-) sign
Use flag "--" to stop switch parsing

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Working random fact generator
Though without infinite time and knowledge of how the site will be designed in the future this may stop working, it still will serve as a simple straight forward starting point. This uses the observation that the only item marked as strong on the page is the single logical line that includes the italicized fact. If future revisions of the page show failure, or intermittent failure, one may simply alter the above to read. $ wget randomfunfacts.com -O - 2>/dev/null | tee lastfact | grep \ | sed "s;^.*\(.*\).*$;\1;" The file lastfact, can then be examined whenever the command fails.

Create a mirror of a local folder, on a remote server
Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

Extract IPv4 addressess from file

find process associated with a port
e.g. fuser 25/tcp (see which pid is listening on smtp)

Backup your OpenWRT config (only the config, not the whole system)
You only have to fill in your administrative account and password, and the router FQDN! I recommand to execute this command not over the internet, because there is no encryption (the username and password will be transmitted in plaintext!)

run a command from within vi without exiting
":! ls -l " results in listing the files in the current directory. pressing "enter" will get you back into vi.


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: