Commands by suprjami (2)

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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" }

follow the content of all files in a directory
The `-q' arg forces tail to not output the name of the current file

sort a JSON blob
For situations where you keep JSON in a VCS and you want your diffs to be sane, such as within a Chef configuration repo.

Search command history on bash
Very handy and time-saving. Do a 'ctrl+ r' on command prompt. You will see a "(reverse-i-search)`':" mark. Just type any sub-string of the command you want to search(provided you have used it sometime in the same session). Keep on searching by repeatedly pressing ctrl+r. Press enter once you get the desired command string.

revert a file with svn

Easily scp a file back to the host you're connecting from
Place in .bashrc and invoke like this: "mecp /path/to/file", and it will copy the specified file(s) back to the desktop of the host you're ssh'ing in from. To easily upload a file from the host you're ssh'ing in from use this: ucp (){ scp ${SSH_CLIENT%% *}:Desktop/upload/* .; }

Replace multiple spaces with semicolon

Fetch all GPG keys that are currently missing in your keyring
For instance, if people have signed your key, this will fetch the signers' keys.

generate random mac-address using md5sum + sed

recursive search and replace old with new string, inside files
If you can install rpl it's simpler to use and faster than combinations of find, grep and sed. See man rpl for various options. time on above operation: real 0m0.862s, user 0m0.548s, sys 0m0.180s using find + sed: real 0m3.546s, user 0m1.752s, sys 0m1.580s


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