Just add them to your '.bashrc'
#-------------------
# Personnal Aliases
#-------------------
alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
# -> Prevents accidentally clobbering files.
alias mkdir='mkdir -p'
alias h='history'
alias j='jobs -l'
alias which='type -a'
alias ..='cd ..'
alias path='echo -e ${PATH//:/\\n}'
alias libpath='echo -e ${LD_LIBRARY_PATH//:/\\n}'
alias print='/usr/bin/lp -o nobanner -d $LPDEST'
# Assumes LPDEST is defined (default printer)
alias pjet='enscript -h -G -fCourier9 -d $LPDEST'
# Pretty-print using enscript
alias du='du -kh' # Makes a more readable output.
alias df='df -kTh'
#-------------------------------------------------------------
# The 'ls' family (this assumes you use a recent GNU ls)
#-------------------------------------------------------------
alias ll="ls -l --group-directories-first"
alias ls='ls -hF --color' # add colors for filetype recognition
alias la='ls -Al' # show hidden files
alias lx='ls -lXB' # sort by extension
alias lk='ls -lSr' # sort by size, biggest last
alias lc='ls -ltcr' # sort by and show change time, most recent last
alias lu='ls -ltur' # sort by and show access time, most recent last
alias lt='ls -ltr' # sort by date, most recent last
alias lm='ls -al |more' # pipe through 'more'
alias lr='ls -lR' # recursive ls
alias tree='tree -Csu' # nice alternative to 'recursive ls'
# If your version of 'ls' doesn't support --group-directories-first try this:
# function ll(){ ls -l "$@"| egrep "^d" ; ls -lXB "$@" 2>&-| \
# egrep -v "^d|total "; }