# number of occur
grep -c "error" logfile.txt
# show context lines before and after match
grep --context=6 successful logfile.txt
# case insensitive
grep -i
# zip files
zgrep -i error *.gz
# display file name
grep -I error *.log
# $_ is a reference to the last parameter that was used
# create dir and then cd to that
mkdir foo && cd $_
# brace
cp /some/path/to/file.txt{,.bak}