Reading is good, but you have to use it as well. So start writing simple scripts and expand upon them. My most frequent starter script tends to be something like:
#!/bin/sh
while read file
process $file
maybe a rename operation,
or copy, or differences, etc...
do
done <<EOD
...a list of files
...that I want to
...process, which
...may have been generated
...by 'ls' or 'find' or 'grep -l'
EOD
I have started scripts that way, which have then grown into some rather large and useful scripts.
For sysadmin type work, you want to get comfortable with ssh and scp, especially the ssh-keygen. Also utilities like 'find' and 'xargs', 'tar', 'rsync' are useful to know about. Learn to use 'rsync -e ssh' for doing networked incremental backups.
For sysadmin work at your company, see if you can find and analyze scripts that your existing sysadmins are using to see what kinds of tasks they are using scripts for. That will help focus your study and practice scripts on areas they need.
Learn about
${variable#pattern}
${variable##pattern}
${variable%pattern}
${variable%%pattern}
I find that these are extremely useful and end up using them constantly. But their power is not always obvious. Learn them, know them inside and out. You will find them useful.
There is so much I could go on about, but I would start to ramble. Just analyze existing scripts, and write your own, especially ones that access other systems via ssh, scp, rsync -e ssh.
Good luck
