เพิ่มช่องว่างก่อนคำสั่ง คำสั่งที่ขึ้นต้นด้วยเว้นวรรคไม่ต้องใส่ในประวัติ:
root@ubuntu-1010-server-01:~# echo foo
foo
root@ubuntu-1010-server-01:~# history
1 echo foo
2 history
root@ubuntu-1010-server-01:~# echo bar
bar
root@ubuntu-1010-server-01:~# history
1 echo foo
2 history
ผู้ชายทุบตี
HISTCONTROL
A colon-separated list of values controlling how commands are
saved on the history list. If the list of values includes
ignorespace, lines which begin with a space character are not
saved in the history list. A value of ignoredups causes lines
matching the previous history entry to not be saved. A value
of ignoreboth is shorthand for ignorespace and ignoredups. A
value of erasedups causes all previous lines matching the cur‐
rent line to be removed from the history list before that line
is saved. Any value not in the above list is ignored. If
HISTCONTROL is unset, or does not include a valid value, all
lines read by the shell parser are saved on the history list,
subject to the value of HISTIGNORE. The second and subsequent
lines of a multi-line compound command are not tested, and are
added to the history regardless of the value of HISTCONTROL.