I've probably found the answer for your question
on Stack Overflow. In the words of Dennis Williamson:
It is likely that you're using a pager such as less or most since the
output of ps aux is longer than a screenful. If so, the following
options will cause (or force) long lines to wrap instead of being
ps aux | less -+S
ps aux | most -w If you use either of the following commands, lines
won't be wrapped but you can use your arrow keys or other movement
keys to scroll left and right.
ps aux | less -S # use arrow keys, or Esc+( and Esc+), or Alt+( and
ps aux | most # use arrow keys, or < and > (Tab can also be used
to scroll right) Lines are always wrapped for more and pg.
ps aux is used in a pipe, the w option is unnecessary since ps
only uses screen width when output is to the terminal.
(Note: this applies to non-embedded Linux, the
ps utility on other Unix variants may work differently.)