Commands by buildingpermit (0)

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Compare two CSV files, discarding any repeated lines
The value for the sort command's -k argument is the column in the CSV file to sort on. In this example, it sorts on the second column. You must use some form of the sort command in order for uniq to work properly.

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"

Add line number count as C-style comments
I often find the need to number enumerations and other lists when programming. With this command, create a new file called 'inputfile' with the text you want to number. Paste the contents of 'outputfile' back into your source file and fix the tabbing if necessary. You can also change this to output hex numbering by changing the "%02d" to "%02x". If you need to start at 0 replace "NR" with "NR-1". I adapted this from http://osxdaily.com/2010/05/20/easily-add-line-numbers-to-a-text-file/.

Generate a playlist of all the files in the directory, newer first
I use this to generate a playlist with all the podcasts I listen to. Ordered from most recent to older.

Read random news on the internet
Access a random news web page on the internet. The Links browser can of course be replaced by Firefox or any modern graphical web browser.

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

macOS: Save disk space by moving apps to external drives
Because Mac app bundles contain everything in one place, it makes running them from anywhere, including from a device such as a USB flash drive or external HDD, possible. So if your Mac has a mere 256GB of storage (as mine does), you can free up large quantities of disk space by storing apps like, say, Xcode on external devices.

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" }

bulk rename files with sed, one-liner
Far from my favorite, but works in sh and with an old sed that doesn't support '-E'

Display the standard deviation of a column of numbers with awk

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