Login or Register to Ask a Question and Join Our Community


UNIX for Dummies Questions & Answers

Difference between plain "uniq" and "uniq -u"

 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers Difference between plain "uniq" and "uniq -u"
# 1  
Old 12-24-2008
Difference between plain "uniq" and "uniq -u"
Dear all,

It's not entirely clear to me from manpage the difference between them.
Why we still need "-u" flag?

- monkfan
# 2  
Old 12-24-2008
Actually the man page is very clear and you can better understand that with an example.

Code:
>file
abc
def
abc

try these commands
Code:
uniq file
sort file | uniq -u
uniq -u file

Basically this is the difference -

uniq - removes duplicates from *sorted* files
- u => prints only the unique ones and not the lines that are duplicates
# 3  
Old 12-24-2008
In my experience, it's only useful when combined with the -c switch, eg:

foo.txt
Code:
asdf
ghjk
qwer
tzui
asdf

Code:
$ sort foo.txt | uniq -c
      2 asdf
      1 ghjk
      1 qwer
      1 tzui
$ sort foo.txt | uniq -cu
      1 ghjk
      1 qwer
      1 tzui
$ sort foo.txt | uniq -cd
      2 asdf

# 4  
Old 12-28-2008
Quote:
sort foo.txt | uniq -c
Two commands are not needed for this just 1 would do using associating arrays

Code:
awk '{ arr[$0]++ }END { for ( i in arr ) { print i, arr[i] } }' filename

 
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. AIX

Apache 2.4 directory cannot display "Last modified" "Size" "Description"

Hi 2 all, i have had AIX 7.2 :/# /usr/IBMAHS/bin/apachectl -v Server version: Apache/2.4.12 (Unix) Server built: May 25 2015 04:58:27 :/#:/# /usr/IBMAHS/bin/apachectl -M Loaded Modules: core_module (static) so_module (static) http_module (static) mpm_worker_module (static) ... (3 Replies)
Discussion started by: penchev
3 Replies

2. Shell Programming and Scripting

Bash script - Print an ascii file using specific font "Latin Modern Mono 12" "regular" "9"

Hello. System : opensuse leap 42.3 I have a bash script that build a text file. I would like the last command doing : print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt where : print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
1 Replies

3. UNIX for Dummies Questions & Answers

Using "mailx" command to read "to" and "cc" email addreses from input file

How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address and column 3 contains “cc” e-mail address to include with same email. Sample input file, email.txt Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies

4. Shell Programming and Scripting

Show "uniq -c" results only for more than X occurrences

Say I have test.txt with the following data: user1 mailbox11 IP1 user1 mailbox12 IP2 user2 mailbox21 IP1 user3 mailbox31 IP1 user1 mailbox11 IP1 user1 mailbox11 IP1 user1 mailbox11 IP1 user1 mailbox12 IP2 user2 mailbox21 IP1 user2 mailbox21 IP1 user2 mailbox21 IP1 user2 mailbox21 IP1... (4 Replies)
Discussion started by: striker4o
4 Replies

5. Shell Programming and Scripting

awk command to replace ";" with "|" and ""|" at diferent places in line of file

Hi, I have line in input file as below: 3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL My expected output for line in the file must be : "1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL" Can someone... (7 Replies)
Discussion started by: shis100
7 Replies

6. Solaris

difference between "root" and "usr" packages

Hi, could someone pls enlighten me on the difference between the "root" package and "usr" package? Like in this example: pkginfo -l SUNWGtku | grep -i desc DESC: GTK - The GIMP Toolkit (Usr) and pkginfo -l SUNWGtkr | grep -i desc DESC: GTK - The GIMP Toolkit (Root)... (6 Replies)
Discussion started by: masloff
6 Replies

7. Shell Programming and Scripting

cat $como_file | awk /^~/'{print $1","$2","$3","$4}' | sed -e 's/~//g'

hi All, cat file_name | awk /^~/'{print $1","$2","$3","$4}' | sed -e 's/~//g' Can this be done by using sed or awk alone (4 Replies)
Discussion started by: harshakusam
4 Replies

8. UNIX for Dummies Questions & Answers

question about "uniq"

I'm sure this is very basic, but I'm just a beginner, so please be kind. :-) I think I understand how to "sort" a text file, and how to save the unique lines to a new file: sort file.txt | uniq > newfile.txt Now, I want to do something similar, but only the first few entries of the line... (1 Reply)
Discussion started by: zac100
1 Replies

9. UNIX for Dummies Questions & Answers

Explain the line "mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'`"

Hi Friends, Can any of you explain me about the below line of code? mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'` Im not able to understand, what exactly it is doing :confused: Any help would be useful for me. Lokesha (4 Replies)
Discussion started by: Lokesha
4 Replies
Login or Register to Ask a Question