It's important that sections of ~/.bashrc be ordered correctly to prevent such issues. Just because someone tells you to add something to the *end* of your .bashrc does not mean that's necessarily the best place to put it.
1) some boilerplate, including checking whether the shell is actually interactive bash, plus: trap '' SIGINT SIGQUIT # ignore ctrl-C and ctrl-\ 2) any essential initialization - including variables like HISTFILE, HISTFILESIZE, HISTSIZE, TERM, TRUECOLOR, TZ and shopt/set options. 3) optionally (useful if the remainder of the file might be "slow"): trap 'exit $?' SIGINT SIGQUIT # abort login on ctrl-C and ctrl-\ 4) read/include (“.”) files: - recommended by your OS - mandated by your system administrator - for any frameworks you want to use (ble, zcomp - containing your own customisations (Grouping like this is useful, but some re-ordering may be required to accommodate interdependencies.) 5) finish with: trap - SIGINT SIGQUIT # normal handling for ctrl-C and ctrl-\ -Martin PS: my own preferred approach is to set HISTFILE=$HOME/.bash_history.d/$EPOCHSECONDS.$$ so that (a) bashrc can't erase old history, and (b) history from different sessions isn't interleaved. To recover old history, I use something like: while read histfile ; do history -r "$histfile" ; done < <( find ~/.bash_history.d/* -mtime -14 -print ) which relies on the `*` glob to sort the histfiles into time order. (I leave it to my heirs to revise this before 20 November 2286.) On Tue, 18 Mar 2025 at 05:26, Ionut Nicula <nicula.i...@gmail.com> wrote: > Configuration Information [Automatically generated, do not change]: > Machine: x86_64 > OS: linux-gnu > Compiler: gcc > Compilation CFLAGS: -g -O2 -fstack-protector-strong -Wformat > -Werror=format-security -Wall > uname output: Linux zinc 6.1.0-32-amd64 #1 SMP PREEMPT_DYNAMIC Debian > 6.1.129-1 (2025-03-06) x86_64 GNU/Linux > Machine Type: x86_64-pc-linux-gnu > > Bash Version: 5.2 > Patch Level: 15 > Release Status: release > > Description: > Had this weird issue on my work laptop where my .bash_history file > would get truncated from time to > time, and I had no idea what caused it because no background or > foreground process should modify > .bash_history in that way. > > Turns out that this was caused by pressing Ctrl+C when ~/.bashrc > was being evaluated. > > Normally, on my PC, ~/.bashrc is very lightweight and I have a > very very small window when I can > press Ctrl+C and have it aborted. But at work, the init takes > longer (~1 second) and I sometimes > press Ctrl+C to abort it, run a command that doesn't depend on the > .bashrc init, and then close > the shell. But this effectively sets the history length to 500 > (the system default, instead of > my actual infinite length in ~/.bashrc). When this happened > before, I didn't notice it right > away. I only noticed like a couple of hours after I accidentally > truncated my bash history file, > so I was very confused. It happened like 8 times in the last 12 > months and it happened again > today, so I decided to spend a bit of time on it and find the issue. > > Repeat-By: > 1. Write a ~/.bashrc file that sets the history length to allow > infinite number of entries. > 2. Write a global bash config that sets the history length limit to > 500. > 3. Add 1000 lines to the bash history file. > 4. Add a command like 'sleep 999' to your ~/.bashrc before the > lines that set up the infinite > history size, in order to simulate a slow initialization. > 5. Start a new bash instance, press Ctrl+C, and notice how > .bash_history gets truncated to 500 > lines. > > Fix: > I'm not sure what tweaks are 'allowed' here, but ideally, I would > like some kind of flag that > simply closes the bash instance if I ever press Ctrl+C during > .bashrc evaluation because, as my > report demonstrates, it can quite easily lead to weird and > confusing behavior. I'm not sure if > my suggested 'fix' is allowed (or makes sense) to be the default > behavior. > >
