Just some Ubuntu/Unix commands that I seem to find very useful but can be hard to remember at times.
PDF Concatenation
pdftk in1.pdf in2.pdf cat output out1.pdf
Its annoying that nautilus doesn't integrate this by default, so I could select some PDF's then right click and choose merge. Luckily I can do this with the fairly simple Nautilus Actions Configuration app. But this takes time and the average user doesn't have the time to research these things on how to do it themselves. Of course this could be extended further to match what you can do from the command line, such as choose some method of ordering the files, or choose to do weird things such as rotate every second page. Sure you want to keep things simple, so as a start it would be great to see something basic. There are probably even nautilus scripts in the repositories out there that do this exact thing, but you spend half your time finding them and installing them. I think this should be enabled by default, or put in some options page somewhere.
Truncate an mp3 file
mpgsplit input.mp3 [00:00:20-00:00:58] -o output.mp3
It appears that this doesn't re-encode so it seems to run very fast.
Mount an ISO
sudo mount -o loop ~/disk.iso /media/cdrom0
Strip audio from a video file
ffmpeg -ab 320k -i in.mov outaudio.mp3
Unfortunately when I left out the bit rate, it defaulted to 14K or something much lower than what the source file was using.
Search all files in the current directory for some string
find . -exec grep "searchthisstring" '{}' \; -print find . -exec grep -q "searchthisstring" '{}' \; -print
Trim and nup pdfs
pdfnup --nup 2x2 --pages 26-140 --trim "1cm 1cm 1cm 1cm" infile.pdf
Wake from Suspend
sudo rtcwake -u -s 12600 -m on
... then you need to manually put the computer in suspend and 12600 seconds later the computer will resume.
Susped
pm-suspend
Shutdown
sudo shutdown -h now sudo shutdown -r now
... the -h means halt (shutdown), -r means reboot.
Tar and Gz all the files in a directory
tar -cvfz file.tar.gz *
Get file info from an HTTP server without downloading
wget -S --spider http://www.site.com/file