How do i Reverse output already piped from sort and cut commands

Question

I have to take user input of there UID then use it to reference the /etc/passwd directory and sort the data by first name and display only username,firstname,lastname in that order. The problem i'm having is sorting the output. if i use a command like

cat /etc/passwd |grep  $id_prefix | sort | cut -d: -f1,5

The output sorts by username and displays in a lastname, firstname order. I know I could change the command to something like.

cat /etc/passwd |grep  $id_prefix | sort | cut -d: -f5 | sed 's/\([^ ]*\)[ ][ ]*\([^ ]*\)/\2 \1/'

Then I will get the output sorted and cut how I want it but it will not contain FIELD1, the usernames. How would I write this to correctly display all the fields I need and also sort them?

Answer 1

You could do something like this:

awk -F: '{ print $1"   "$5 }' /etc/passwd | sort -k2

This will parse the username and comment fields from /etc/passwd and sort on the second field which will be the first name of the user, provided they are listed in first name and last name order.

Here is an example of incorporating grep:

grep "500\|501\|502" /etc/passwd | awk -F: '{ print $1"    "$5 }' | sort -k2

jira    Atlassian JIRA
dick    Richard Jameson
bob    Robert Gillespie

EDIT:

Use this to reverse the lastname, firstname ordering from the /etc/passwd file:

awk -F: '{ print $1"   "$5 }' /etc/passwd | awk '{ print $1"    "$3" "$2 }' | sort -k2

The above example modified for lastname, firstname in the /etc/passwd file:

grep "500\|501\|502" /etc/passwd | awk -F: '{ print $1"    "$5 }' |  awk '{ print $1"    "$3" "$2 }' | sort -k2

This works if there are not, and should not be, any commas separating first/last, last/first names.

EDIT (the second):

Since the last/first names are comma separated, this should work:

awk -F: /$id_prefix/'{ print $1"    "$5 }' /etc/passwd | awk -F, '{ print $1"    "$2 }' | awk '{ print $1"    "$3"    "$2 }' | sort -k2

Thank you @Jidder for recommending not piping from grep to awk.

Answer 2

You have to do it:

grep mohsen /etc/passwd | awk -F':' {'split($5,a,",");printf "username is :%s ,uid is: %s , name is %s \n",$1,$3,a[1]  '}

Output is:

username is :mohsen ,uid is: 1000 , name is Mohsen Pahlevanzadeh

Answer 3

I think you could get away with something like this:

grep $id_prefix /etc/passwd | cut --delimiter: --fields=1,5 | sort --field-separator=: --key=2

You could also add --ignore-case option to sort if needed in your context. Check its docs for more options.

Answer 4

Don't know why people are piping grep into awk.
You could do it all in awk. This presumes that first and last name are separated by a space.
Where USERNAME is the search term

awk -F: '/USERNAME/{split($5,a," ");print $1,a[2],a[1]}' etc/passwd