Introduction
Let’s say we want to change our git username to another one. Instead of checking manually if the username is already taken, we can automate this process by writing a script named fgitusr. The content of the script looks like this:
Code
# Check regex rules
if [[ !("$1" =~ ^[0-9a-zA-Z]{1}[0-9a-zA-Z\-]*[0-9a-zA-Z]{1}$) ]]; then
echo "$1 DOESN'T MATCH REGEX"
exit 1
fi
# Check if usersname exists
curl --output /dev/null --silent --head --fail "https://github.com/$1"
if [ $? -eq 0 ]; then
echo "USER $1 EXISTS";
else
echo "USER $1 DOESN'T EXIST";
fi
The main idea is that we use curl to look if the url https://github.com/<username> is a valid link. If it is, then the user exist.
Output
When user is found:
$ fgitusr foo
USER foo EXISTS
When user is not found:
$ fgitusr fobarfoo
USER fobarfoo DOESN'T EXIST
When user doesn’t respect regex rules:
$ fgitusr foo_bar
foo_bar DOESN'T MATCH REGEX
Conclusion
The advantage of searching usernames with this method, is that you can automate the process. For example you can use a for loop over multiple usernames to check if every username is available:
$ for u in "abc" "bcd" "cde"; fgitusr $u
USER abc EXISTS
USER bcd EXISTS
USER cde EXISTS