Commands using cat (514)

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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"

Picture Renamer
jhead is a very nice tool to do all sorts of things with photographs, in a batch-oriented way. It has a specific function to rename files based on dates, and the format I used above was just an example.

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

aptitude easter eggs
this is a reference to Antoine de St. Exupery's "The Little Prince"

Create a new file

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Annotate tail -f with timestamps

Add page numbers to a PDF
Put this code in a bash script. The script expects the PDF file as its only parameter. It will add a header to the PDF containing the page numbers and output it to a file with the suffix "-header.pdf" Requires enscript, ps2pdf and pdftk.

Bash alias to output the current Swatch Internet Time
Output the current time in Swatch “Internet Time”, aka .beats. There are 1000 .beats in a day, and @0 is at 00:00 Central European Standard Time. This was briefly a thing in the late 1990s. More details: https://2020.swatch.com/en_ca/internet-time/ The alias is rather quote heavy to protect the subshell, so the bare command is: $ echo '@'$(TZ=GMT-1 date +'(%-S + %-M * 60 + %-H * 3600) / 86.4'|bc)

Given process ID print its environment variables
Same as previous but without fugly sed =x


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