Simple Filters

Command                                                       Function
head                                               􀊊used to display the first few records (10 records by default)
head stud                                           Displays first 10 records by default
head -5 stud                                       Displays first 5 records
head -1 stud | wc –c                                 length of first record
tail􀊊                                                 used to  display the last few records (10 records by default)
tail stud                                                   Displays last 10 records by default
tail -5 stud | tee last5                               Last 5 records listed & stored in file last5 using tee
cut􀊊used to extract specific field         The d option specifies the delimiter and f for specifying the field list.                                                              The c option may be used if extraction is done character wise
cut –d \| -f 1,3,4 stud                                          Fields 1,3,4 listed
cut –d \| -f 2-4 stud                                            Fields 2,3,4 listed
paste –d \| list1 list2                                 merges two cut files list1 and list2
sort                              􀊊reorders the file as per ASCII sequence. The t option is used to specify delimiter and k option to specify the field
sort stud                                                Sorted on 1st column by default
sort –t \| -k 3                                                stud Sort as per 3rd column
sort –c stud                                           Check if file is sorted using c option
sort -t \| -k 4,4 -k 3,3
stud
Sorting on secondary keys
sort -t \| -nr –k 4 stud                        Sort on numeric field using n option, r for reverse
uniq stud                                        Display unique entries in a sorted file

tr􀊊translates characters. Can be used to change text case. It works with standard input <
tr '[a-z]' '[A-Z]' < stud Changes text to upper case
nl􀊊display file content with lines numbered. The s option is used to specify separator
nl –s "|" stud Displays entries numbered with separator |