git log pipe to sed

[ZikiHero]

In Commits tab I can see all commits in current branch and there are initials of person who made that commit. I wanted to implement similiar feature to allBranchesLogCmd which looked like this
git log --pretty=format:"%C(yellow)%h %C(auto)%aN %C(cyan)%ar %C(auto)%d %C(reset) %s" --graph --all --color=always --date-order.
After some reserch I found out, that git log can't shorten the author name to only name initials. My idea was that if git log doesn't support it, I can pipe it to sed. My sed command looks like this
sed -E "s/^(((\x1b\[[0-9;]*m)|[ *|\\/_.])+ \x1b\[[0-9;]*m[a-z0-9]{7} \x1b\[[0-9;]*m)(([A-ZŠČŘŽÚ])(\S+))(( ([A-ZŠČŘŽ])(\S+))+)/\1\5\9/g"
and it produces this (colored):

*   1d79558 DV 5 hours ago  (HEAD -> xxx)  xxx
|\  
* \   9ca5ecd PČ 28 hours ago  (xxx)  xxx
|\ \  
| * | 495eca8 PČ 28 hours ago   Fix off mode
| | * 2182e72 LS 2 days ago  (xxx)  SDRAM CLK 80 MHz -> 135 MHz
| |/  
|/|   
| * f6c0210 PČ 3 days ago   Added events and off mode supoort
|/  
* fbd56ad DV 5 days ago   infotab refactoring (use of cached scrollable)

After applying changes to allBranchesLogCmd: 'git log --pretty=format:"%C(yellow)%h %C(auto)%aN %C(cyan)%ar %C(auto)%d %C(reset) %s" --graph --all --color=always --date-order | sed -E "s/^(((\x1b\[[0-9;]*m)|[ *|\\/_.])+ \x1b\[[0-9;]*m[a-z0-9]{7} \x1b\[[0-9;]*m)(([A-ZŠČŘŽÚ])(\S+))(( ([A-ZŠČŘŽ])(\S+))+)/\1\5\9/g"' I am getting following: "fatal: ambiguous argument '|': unknown revision or path not in working tree. Use '--' to separate paths from revisions, like this: 'git [...] -- [...]'".

Also I would like to know if there is a way to have each person having unique color of his initials as it is in Commits tab.