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check open ports without netstat or lsof

force unsupported i386 commands to work on amd64
The above was done using the i386 flashplayer plugin, and was installed on a AMD64 machine running an AMD64 kernel and AMD64 programs. the resulting plugin install ultimately didn't work for swiftfox (but worked for iceweasel) without also covering it with a nspluginwrapper which took a bit of fenangaling to get to work (lots of apt-getting) but it is a nice feature to be able to trick installers that think you need i386 into running on a amd64, or at least attempting to run on amd64. Enjoy

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

chmod - change file permissions of a file to be similar of another

remove hostname from known_hosts

Rename files in batch

recursive reset file/dir perms
Good for fixing web permissions. You might also want to do something like this and skip files or directories that begin with a period: $ find public_html/stuff -not -name ".*" \( -type d -exec chmod 755 {} + -o -type f -exec chmod 644 {} + \) ...or include a special case for scripts: $ find public_html/stuff -type d -exec chmod 755 {} + -or -type f -name "*.pl" -exec chmod 755 {} + -or -exec chmod 644 {} +

List files with quotes around each filename

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" }

Do a search-and-replace in a file after making a backup
sed already has an option for editing files in place and making backup copies of the old file. -i will edit a file in place and if you give it an argument, it will make a backup file using that string as an extension.


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