Some useful Unix commands:

ssh -X username@hostname
The -X option enables X11 forwarding, which means that you can remotely open OpenOffice documents or GNU Emacs windows or R graphics devices.

sort -k i,i -k j,j filename
The sort command can sort on multiple fields, specified in order by the -k option. (Add n to sort by numerical value.)

cat filename | sed 's/find_text/replace_text/g' > output
Global search and replace using the stream editor in Unix. Same command in vim but need to preface with %.