Finishing second week notes
VIM editor
How in the text copy, paste, delete rows, delete all, and finding rows alphabetically
Pipes and redirection
cat /etc/issue | tr [:lower:] [:upper:] > /tmp/issue.out
4, the / root / file list display in a row, and file name separated by spaces
ls /root |tr '\n' ' '
5, calculates the sum of 1 + 2 + 3 + 4 + 99 + 100 + ..
echo {1..100} | tr '' + | bc
6, delete the text file in the windows of the carriage return character, that is, "\ r"
CAT win.txt | TR -d '\ r'> win2.txt
hexdump -c win2.txt