Commands using echo (1,545)

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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"

Convert PDF to JPEG using Ghostscript
Converting your PDF file to JPEG images. You can set resolution by -r option (default: 72dpi).

Swap a file or dir with quick resotre
This lets you replace a file or directory and quickly revert if something goes wrong. For example, the current version of a website's files are in public_html. Put a new version of the site in public_html~ and execute the command. The names are swapped. If anything goes wrong, execute it again (up arrow or !!).

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" }

Then end of the UNIX epoch
http://en.wikipedia.org/wiki/Year_2038_problem Some other notable dates that have passed: $ date -d@1234567890 $ date -d@1000000000

a function to find the fastest DNS server
http://public-dns.info gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.

Updates your no-ip.org account with curl

Project your desktop using xrandr
HDMI-1 is the interface in the example, which can be obtained just by typing xrandr and surfing through the output. There are a hell lot of configurations that can be done but I prefer auto because it works in most cases. $ Lifesaver

check open ports without netstat or lsof

for newbies, how to get one line info about all /bin programs
Get simple description on each file from /bin dir, in list form, usefull for newbies.


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