cut

cut

cut in unix  is not exactly the same as the cut option in gui based windows. cut is

a text  manipulative command that is widely used in  shell scripting .

You can cut  fields, same as the way you do by using awk,  or cut  a  required number of characters from the lines of a file.

Example1)

You have to read only a particular column  from a file,use cut with –d option along with  -f.

Suppose the file contains the following content.

/home/khan $ cat  workingTime.txt

    Ist                                       II                                      Break                               III                                     IV

10:00-:11:20am     11:25am-12:30pm          2:30-1:45pm          1:45-3:00pm               3:05-4:30pm

10:00-:11:15am     11:20am-12:40pm          12:40-1:30pm         1:30-2:45pm              2:50-4:20pm

10:00-:11:00am     11:00am-12:00pm          12:00-1:30pm         1:35-3:00pm              3:05-4:15pm

10:00-:11:20am     11:25am-12:30pm          12:30-1:45pm         1:45-3:00pm              3:05-4:30pm

10:00-:11:15am     11:20am-12:25pm           12:25-1:30pm         1:30-2:45pm             2:50-4:20pm

 Five    rows   for    five  working  days

/home/khan $

Note: here there is only one space between each entry in the column. I have used  longer spaces for better visibility.

To get only the timings for  the break, use the following command.

/home/khan $ cut  –f3   –d   “  “    workingTime.txt

       Break          

2:30-1:45pm  

12:40-1:30pm

12:00-1:30pm

12:30-1:45pm

 12:25-1:30pm

 for

similarly if the columns in the  file is separated by some other characters such as  , or | or – etc  include them as an argument after –d

Example 2)

suppose  you have  a variable which stores a date in a particular format  and you want to access the month, year and day, use it as shown by the script.

/home/khan $ cat  bday.sh

echo "ENTER  YOUR  BIRTH  DAY (MMDDYYYY) "

read b_date

b_yr=`echo $b_date | cut –c5-8`

dt=`echo $b_date|cut –c3-4`

mon=`echo $b_date | cut –c1-2`

case   $mon   in

        01) month=JAN;;

        02) month=FEB;;

        03) month=MAR;;

        04) month=APR;;

        05) month=MAY;;

        06) month=JUN;;

        07) month=JUL;;

        08) month=AUG;;

        09) month=SEP;;

        10) month=OCT;;

        11) month=NOV;;

        12) month=DEC;;

esac

echo “YOU WERE BORN ON  $month  MONTH”

Example 3)

It is needed to display all  the characters starting from nth character, use cut as shown.

/home/khan$ cat  expense.txt

145.8967

134.56

911.342

100.67890

234.5

867.4545

If  you need to fetch the decimal value,

/home/khan$ cut   -c4-  expense.txt

.8967

.56

.342

.67890

.5

.4545

Similarly if you want to

1) cut all starting characters up to 4^th character  

2)1^st 2 characters then 5 ^th to 7^th character use

cut  -c -4 and 

cut   -c -2,5-7  respectively.

Example 4)

There is sometimes an unusual situation where you want to cut  only  backwards.

i:e you only know that nth field starting from end of a line is fixed and you want to cut the nth character. Here it is done with cut  and  rev command (only in  Aix,Linux. If you do not have rev use this url http://www.askdavetaylor.com/where_can_i_find_the_rev_utility_for_solaris.html  to get a c code  for rev and compile and save it in a path defined in your $PATH variable).

Consider a file which contains patterns as shown.

/home/khan$  cat  fool-art-works.lst

Heart_shaped_rice_1853.jpg

Oils_And_Sand_Stones_Tree_3567.png

Beetles_Moths_Sun_Butter_20954.bmp

Cats_Fight_Dogs_Donkeys_450.jpeg

You may have to access  the code number and file extension which are fixed to appear as last 2 fields  among all the lines.

Use cut and rev as follows.

/home/khan$  for  line in `cat   fool-art-works.lst `

>do

>echo   “$line”  |   rev |  cut   -f1  -d  “_”   |  rev

>done

_1853.jpg

_3567.png

_20954.bmp

_450.jpeg

You can  further use pipes and cuts to separate number and extension from these line  strings..now you know how…!!