SEARCH TEXT IN A FILE
grep: it searches for patterns in each file and prints each line that matches a pattern:
With the option -i it will ignore case distinctions:
With the option -R it will search all files under each directory, recursively:
MISCELLANEOUS
history: it will list up to 500 previously executed commands:
alias: it is used to define temporary aliases in our shell session:
unalias: it is used to remove an alias:
