awk

cut
How to cut lines separated by multiple spaces?
How to get list of User-Agent from access log

To list all kernels available in your server, run

awk -F\' '$1=="menuentry " {print i++ " =  "$2}' /etc/grub2.cfg

Example

root@server48 [~]# awk -F\' '$1=="menuentry " {print i++ " =  "$2}' /etc/grub2.cfg
0 =  CloudLinux (3.10.0-962.3.2.lve1.5.24.10.el7.x86_64) 7.6 (Vladimir Lyakhov)
1 =  CloudLinux (3.10.0-962.3.2.lve1.5.24.9.el7.x86_64) 7.6 (Vladimir Lyakhov)
2 =  CloudLinux (3.10.0-962.3.2.lve1.5.24.8.el7.x86_64) 7.6 (Vladimir Lyakhov)
3 =  CloudLinux (3.10.0-962.3.2.lve1.5.24.5.el7.x86_64) 7.5 (Viktor Gorbatko)
4 =  CloudLinux (3.10.0-962.3.2.lve1.5.24.4.el7.x86_64) 7.5 (Viktor Gorbatko)
root@server48 [~]#

To print all users from /etc/passwd, run

cat /etc/passwd | awk -F: '{print $1}'

To list all file names from ls -l command, run

ls -l | awk -F' ' '{print $9}'