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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"

Get a list of the top 10 heaviest tables in your mysql database - useful for performance diagnostics

Perform a C-style loop in Bash.
Print 0 through 99, each on a separate line.

Selecting a random file/folder of a folder
Also looks in subfolders

ssh: change directory while connecting
Useful to create an alias that sends you right in the directory you want : alias server-etc="ssh -t server 'cd /etc && $SHELL'"

copy remote ssh session output to local clipboard
ssh from local to remote and pipe output of file to the local clipboard

Exclude inserting a table from a sql import
Starting with a large MySQL dump file (*.sql) remove any lines that have inserts for the specified table. Sometimes one or two tables are very large and uneeded, eg. log tables. To exclude multiple tables you can get fancy with sed, or just run the command again on subsequently generated files.

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" }

IFS - use entire lines in your for cycles
When you use a "for" construct, it cycles on every word. If you want to cycle on a line-by-line basis (and, well, you can't use xargs -n1 :D), you can set the IFS variable to .

convert a web page into a pdf
This uses the "command-line print" plugin for Firefox (http://torisugari.googlepages.com/commandlineprint2). This same plugin can also produce PNGs. On *nix, the file must exist; therefore the touch bit in front. Also, firefox seems to ignore saved user preferences when "printing" this way (margins, header, footer, etc.), so I had to tweak my ~/.mozilla/firefox/xxxxxxxx.default/prefs.js file by hand. Yup, that's *prefs.js* not user.js - apparently, firefox ignores my user.js file too...


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