קטגוריה: טיפים לשורת הפקודה

cut
The cut command has the ability to cut out characters or fields.
cut use delimiters to determine where to split the  fields.

By default, cut's delimiters are stored in the shell variable IFS (Input Field Separators).
Typing:

set | grep IFS

will show what the separator characters currently are; at present, IFS is either:
a. tab
b. new line
c. space.

Usage:
cut [-d char] [-c|-f] list [files...]
-d: define field delimiter (tab by default)
-c list:  cut by column position
-f list: cut by field number

Examples:

cat /etc/passwd | cut -d:  -f1,7
or:
cut -d:  -f1,7 /etc/passwd

will display:
field 1 (username)
field 7 (default shell)
from /etc/passwd.

cut -d:  -f1,6-7 /etc/passwd
will display:
field 1 (username)
field 6 (home directory)
field 7 (default shell)ut

who | cut -d' ' -f1
will display the username that
currently login to the system

cut -c1-7 /etc/tstab
will display the first 7 characters
in /etc/fstab (for each line)

tee

redirections are great tools for sending command output (stdout) to a file (other than the screen).  pipe make the output of one command as input of other command

But if you want, in a single command, to do two things:
display the command output on the screen and write it to a file. In this case you  should use the tee command

Examples:
ls | tee ls.txt
ls | tee -a ls.txt

the -a option will append the file (default is overwrite)

These commands will display the contents of the current directory on the screen, and write the same information to ls.txt file