CODEWITHSUNDEEP
regexgrepposix
TetsuyaGR
TetsuyaGR

Reputation: 25

Howto check if the first 4 characters of first name and first 4 characters of last name appear in the username

I have a UNIX password file and I need to find, using grep, the entries where:

the first 4 characters from first name and first 4 characters from the last name are inside the username.

This is my attempt:

grep -iE '^[^:]*([^:]{4})[^:]*([^:]{4})([^:]*:){4}(\1|\2)[^: ]* (\1|\2)'

And it does actually matches in some lines like these:

ldapsync:x:1118:65534:LDAP Synchronization,,,:/home/system/ldapsync:/bin/tcsh
johnkene:x:1943:1056:John Kennedy:/home/user/johnkene:/bin/tcsh

But it doesn't match in lines like these:

camad15:x:2674:1000:CAMAD2015 CAMAD2015:/home/user/camad15:/bin/sh

Upvotes: 1

Views: 4767

Answers (1)

anubhava
anubhava

Reputation: 785541

This job suits more to awk than grep because of structure of each record delimited by a character.

You may use this awk:

awk -F: '{
   split($5, a, / /)
   f4 = tolower(substr(a[1], 1, 4))
   l4 = tolower(substr(a[2], 1, 4))
}
index($1, f4) && index($1, l4)' /etc/passwd


ldapsync:x:1118:65534:LDAP Synchronization,,,:/home/system/ldapsync:/bin/tcsh
camad15:x:2674:1000:CAMAD2015 CAMAD2015:/home/user/camad15:/bin/sh

Upvotes: 3

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