In class, we saw several tools that can be used for exploring text corpora on the command line. Those, along with some others that might be useful to you as the semester progresses, include:
cat
less (and more)
head
tail
perl
sed
awk
grep
sort
uniq
The man command will give help on any of those (and many other!) unix tools.
The perl command we used was perl -ple "s/\s/\n/g".