使用grep和cut过滤文本文件以仅显示以'm'，'w'或's'开头的用户名及其主目录

Question

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
sys:x:3:1:sys:/dev:/usr/sbin/nologin
games:x:5:2:games:/usr/games:/usr/sbin/nologin
mail:x:8:5:mail:/var/mail:/usr/sbin/nologin
www-data:x:33:3:www-data:/var/www:/usr/sbin/nologin
backup:x:34:2:backup:/var/backups:/usr/sbin/nologin
nobody:x:65534:1337:nobody:/nonexistent:/usr/sbin/nologin
syslog:x:101:1000::/home/syslog:/bin/false
whoopsie:x:109:99::/nonexistent:/bin/false
user:x:1000:1000:edco8700,,,,:/home/user:/bin/bash
sshd:x:116:1337::/var/run/sshd:/usr/sbin/nologin
ntp:x:117:99::/home/ntp:/bin/false
mysql:x:118:999:MySQL Server,,,:/nonexistent:/bin/false
vboxadd:x:999:1::/var/run/vboxadd:/bin/false

this is an /etc/passwd file I need to do this command on. So far I have:

cut -d: -f1,6 testPasswd.txt | grep ???

that will display all the usernames and the folder associated, but I'm stuck on how to find only the ones that start with m,w,s and print the whole line.

I've tried grep -o '^[mws]*' and different variations of it, but none have worked.

Any suggestions?

Answer 1

Easier to do with awk:

awk 'BEGIN{FS=OFS=":"} $1 ~ /^[mws]/{print $1, $6}' testPasswd.txt

sys:/dev
mail:/var/mail
www-data:/var/www
syslog:/home/syslog
whoopsie:/nonexistent
sshd:/var/run/sshd
mysql:/nonexistent

Answer 2

Try variations of

cut -d: -f1,6 testPasswd.txt | grep '^m\|^w\|^s' 

Or to put it more concisely,

cut -d: -f1,6 testPasswd.txt | grep '^[mws]'

That's neater especially if you have a lot of patterns to match.

But of course the awk solution is much better if doing it without constraints.