Commands by giuseppe_rota (1)

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openssl Generate Self Signed SSL Certifcate
generating self signed ssl certificate to use in dovecot postfix nginx Self signed certificates can be used for private encryptions between server and client and must be manually accepted on browser/ client

Replace "space" char with "dot" char in current directory file names

split a file by a specific number of lines
Splits the file "my_file" every 500 lines. Will create files called xx01 xx02 and so on. You can change the prefix by using the -f option. Comes in handy for splitting logfiles for example. I am using it for feeding a logfile parser with smaller files instead of one big file (due to performance reasons)

list files recursively by size

Recursive find and replace file extension / suffix (mass rename files)
Find recursively all files in ~/Notes with the extension '.md' and pipe that via xargs to rename command, which will replace every '.md' to '.txt' in this example (existing files will not be overwritten).

Get playlist for Livestream on YouTube

list files recursively by size

delete duplicate lines from a file and keep the order of the other lines
i wanted to delete all duplicate lines from .bash_history and keep the order of the other lines. the command cat's the file and adds line numbers, then sorts by the second column. afterwards uniq omits repeated lines, but skips the first field (the line number). then it sorts by the line numbers and at the end cuts the numbers off.

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" }

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"

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