35.14 Cutting Columns or Fields with cut

cut+paste	System V includes a nifty command called cut that lets you select a list of columns or fields from one or more files. We've also included a public-domain version on the disc, for those of you whose systems do without.

You must specify either the -c option to cut by column or -f to cut by fields. (Fields are separated by tabs unless you specify a different field separator with -d . Use quotes (8.14 ) if you want a space or other special character as the delimiter.)

The column(s) or field(s) to cut must follow the option immediately, without any space. Use a comma between separate values and a hyphen to specify a range (e.g., 1-10 , 15 , 20 , or 50- ).

cut is incredibly handy. Here are some examples:

• Find out who is logged in, but list only login names:

  who	% who | cut -d" " -f1

• Extract usernames and real names from /etc/passwd (36.3 ) :

  % cut -d: -f1,5 /etc/passwd
  
  

• Cut characters in the fourth column of file , and paste them back as the first column in the same file:

  paste	% cut -c4 file | paste - file