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list block devices
Shows all block devices in a tree with descruptions of what they are.

Know which modules are loaded on an Apache server
This let you know which modules has loaded the Apache server, very useful to know if the mod_rewrite is ready to use.

generate random number

Change to $HOME - zsh, bash4
To change to $HOME in that manner you need to set a shell option. In zsh it is auto_cd, hence $ setopt -o auto_cd in bash4 it is autocd, hence $ shopt -s autocd What the option does is allow you to cd to a directory by just entering its name. This also works if the directory name is stored in a variable: $ www=/var/www/lighttpd; $www sends you to /var/www/lighttpd. CAUTION: If a command or function name identical to the directory name exists it takes precedence.

phpinfo from the command line
php -i seems to show default not real

easily strace all your apache processes
This one-liner will use strace to attach to all of the currently running apache processes output and piped from the initial "ps auxw" command into some awk.

convert all flac files in a folder to mp3 files with a bitrate of 192 kbps

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

Remove security limitations from PDF documents using ghostscript (for Windows)
#4345 also works under windows

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" }


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