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Find usb device
I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

resize all JPG images in folder and create new images (w/o overwriting)
Convert all jpegs in the current directory into ~1024*768 pixels and ~ 150 KBytes jpegs

Remove everything except that file
it will remove everything except the file names matching you can use also use wildcards

Suspend an ssh session.
This must be typed before any other characters have been entered on the line. Use fg, as usual, to resume the ssh session.

Take a screenshot of the window the user clicks on and name the file the same as the window title
In general, this is actually not better than the "scrot -d4" command I'm listing it as an alternative to, so please don't vote it down for that. I'm adding this command because xwd (X window dumper) comes with X11, so it is already installed on your machine, whereas scrot probably is not. I've found xwd handy on boxen that I don't want to (or am not allowed to) install packages on. NOTE: The dd junk for renaming the file is completely optional. I just did that for fun and because it's interesting that xwd embeds the window title in its metadata. I probably should have just parsed the output from file(1) instead of cutting it out with dd(1), but this was more fun and less error prone. NOTE2: Many programs don't know what to do with an xwd format image file. You can convert it to something normal using NetPBM's xwdtopnm(1) or ImageMagick's convert(1). For example, this would work: "xwd | convert fd:0 foo.jpg". Of course, if you have ImageMagick already installed, you'd probably use import(1) instead of xwd. NOTE3: Xwd files can be viewed using the X Window UnDumper: "xwud <foo.xwd". ImageMagick and The GIMP can also read .xwd files. Strangely, eog(1) cannot. NOTE4: The sleep is not strictly necessary, I put it in there so that one has time to raise the window above any others before clicking on it.

Print number of mb of free ram
This will show the amount of physical RAM that is left unused by the system.

parse html/stdin with lynx
strips html from stdin

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" }

Get the date for the last Saturday of a given month
If your locale has Monday as the first day of the week, like mine in the UK, change the two $7 into $6

tar exclude files or directories
If you want to exclude only one file or directory you should use as --exclude=file_or_directory


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