bash shell history mechanism not reliable?

Question

My typical work flow at the bash prompt consists in typing commands and retrieving them using the Ctrl+R "literal" mechanism.

I have noticed over possibly the last couple of years that there are times where a command randomly disappears from the bash history.

Say I type and execute successfully the following:

$ command A arg1 arg2
$ command B arg3
$ command C arg4

… and type Ctrl+R arg1 — e.g. I get a "failed-reverse-i-search `arg1' ..." error.

Something of interest is that if I follow up with a:

$ history | less

... command A is indeed NOT the history... but I have a line that starts with an asterisk in "column 0" of the history ­— column 0 means the column just left of the column where the commands logged in the history start ­— followed by a blank line.

Has anyone seen anything like this?

This is on a debian/linux stable (buster) running bash 5.0.3.

Answer 1

Has anyone seen anything like this?

Yes. To reproduce:

1. Run echo foo.
2. Run echo bar.
3. ↑↑ so echo foo appears (or Ctrl+rfoo, so echo foo appears, then hold → to get to the end of the line).
4. Hold Backspace, turn echo foo into an empty line, do not execute.
5. ↓, so echo bar appears.
6. Enter to execute echo bar again.

Then history will print an empty entry where you might expect echo foo. It will be marked with * meaning this entry has been edited.

Check the revert-all-at-newline readline variable (see man 3 readline).

• Temporary setting: run bind 'set revert-all-at-newline On' in Bash.
• Persistent setting for new Bash instances: place set revert-all-at-newline On in /etc/inputrc or ~/.inputrc.

Answer 2

If there is a space before your command, it will not be logged.