By default, the root user is locked in Ubuntu. To unlock it, simply run the command below, and provide the new password for the root user when prompted.
|
1 2 3 4 |
sudo passwd root [sudo] password for nik: Enter new UNIX password: Retype new UNIX password: |
Now you should be able to log in as the root user using the su command:
|
1 |
$ su - |
If for some reason you want to lock the
Counting the distinct/unique elements of text file is a common task. Below is an example of doing this is AWK, using sample_data_1.txt.
|
1 2 |
cat sample_data_1.txt \ | awk 'BEGIN{FS="\t"} NR>1{names[$2]=1} END{print length(names)}' |
Here is what is happening above: cat sample_data_1.txt – reading the file piping the data to AWK BEGIN{FS=”\t”} – specifying the field separators of the file NR>1 – Only executing the following