Bash – Why is the bash_history always coming up the same and not updating using non-login shells

bashcommand line

The last few days I've noticed that whenever I shutdown my system (Debian Testing) and fire up a bash session, then press the up arrow key, I get the commands from the first time I cleared the history cache using history -c. I'm not sure how this happened, but even if I clear my history again, then press the up arrow, nice it works, but if I start another shell it doesn't (even less whenever I restart or shutdown or log off).

I've tried everything (even deleting the .bash_history by hand), so I ran out of ideas.

$ echo $SHELL
/bin/bash
$ /bin/bash --version
GNU bash, version 4.2.45(1)-release (i486-pc-linux-gnu)
$ echo $HISTFILE
/home/braiam/.bash_history

When looking for information to add the question, I ran ls -l .bash_history (not to look like a dumb) and found the problem:

$ ls -l .bash_history 
-r--------. 1 braiam braiam 59372 Jul 26 20:18 .bash_history

But running chmod +w .bash_history didn't save the day. Now I wonder how it could end like that…

After deleting the .bash_history file now I have no-history. I checked the .bashrc for clues:

cat .bashrc | grep -i hist
# don't put duplicate lines or lines starting with space in the history.
HISTCONTROL=ignoreboth
# append to the history file, don't overwrite it
shopt -s histappend
# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

Following ash's answer, in a non-login (gnome-terminal) shell:

braiam@bt:~$ echo abacaba; echo $$
abacaba
15372
braiam@bt:~$

Then fired up another non-login shell:

braiam@bt:~$ strace -o e -s 256 -p 15372
Process 15372 attached - interrupt to quit

Went back to the first shell, then type history -a:

braiam@bt:~$ echo abacaba; echo $$
abacaba
15372
braiam@bt:~$ history -a
braiam@bt:~$

In the shell with strace, nothing:

braiam@bt:~$ strace -o e -s 256 -p 15372
Process 15372 attached - interrupt to quit

Here I was almost without hope, so I decided to look at strace manual and found that -o is to dump the result to a file, so cat e resturn this:

cat e
read(0, "\33", 1)                       = 1
read(0, "[", 1)                         = 1
read(0, "A", 1)                         = 1
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
write(2, "history -w", 10)              = 10
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
read(0, "\33", 1)                       = 1
read(0, "[", 1)                         = 1
read(0, "A", 1)                         = 1
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
write(2, "\10a", 2)                     = 2
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
read(0, "\r", 1)                        = 1
write(2, "\n", 1)                       = 1
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig -icanon -echo ...}) = 0
ioctl(0, SNDCTL_TMR_STOP or TCSETSW, {B38400 opost isig icanon echo ...}) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigaction(SIGINT, {0x80a0e30, [], 0}, {0x80e9d00, [], 0}, 8) = 0
rt_sigaction(SIGTERM, {SIG_IGN, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {SIG_IGN, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGALRM, {0x80a1080, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], 0}, {0x80e9d00, [], 0}, 8) = 0
rt_sigaction(SIGTSTP, {SIG_IGN, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGTTOU, {SIG_IGN, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGTTIN, {SIG_IGN, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGWINCH, {0x80a09e0, [], 0}, {0x80e9550, [], SA_RESTART}, 8) = 0
rt_sigaction(SIGINT, {0x80a0e30, [], 0}, {0x80a0e30, [], 0}, 8) = 0
time(NULL)                              = 1378047084
stat64("/home/braiam/.bash_history", {st_mode=S_IFREG|0600, st_size=44, ...}) = 0
open("/home/braiam/.bash_history", O_WRONLY|O_APPEND|O_LARGEFILE) = 3
write(3, "history -w\nhistory -a\n", 22) = 22
close(3)                                = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigaction(SIGINT, {0x80a0e30, [], 0}, {0x80a0e30, [], 0}, 8) = 0
time(NULL)                              = 1378047084
rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
ioctl(255, TIOCSPGRP, [15372])          = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigaction(SIGINT, {0x80a0e30, [], 0}, {0x80a0e30, [], 0}, 8) = 0
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
ioctl(0, TIOCGWINSZ, {ws_row=24, ws_col=80, ws_xpixel=0, ws_ypixel=0}) = 0
ioctl(0, TIOCSWINSZ, {ws_row=24, ws_col=80, ws_xpixel=0, ws_ypixel=0}) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(0, SNDCTL_TMR_STOP or TCSETSW, {B38400 opost isig -icanon -echo ...}) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig -icanon -echo ...}) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, [INT QUIT ALRM TERM TSTP TTIN TTOU], [], 8) = 0
rt_sigaction(SIGINT, {0x80e9d00, [], 0}, {0x80a0e30, [], 0}, 8) = 0
rt_sigaction(SIGTERM, {0x80e9d00, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGTERM, {SIG_IGN, [], 0}, {0x80e9d00, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {0x80e9d00, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {SIG_IGN, [], 0}, {0x80e9d00, [], 0}, 8) = 0
rt_sigaction(SIGALRM, {0x80e9d00, [], 0}, {0x80a1080, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], 0}, 8) = 0
rt_sigaction(SIGTSTP, {0x80e9d00, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGTSTP, {SIG_IGN, [], 0}, {0x80e9d00, [], 0}, 8) = 0
rt_sigaction(SIGTTOU, {0x80e9d00, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGTTOU, {SIG_IGN, [], 0}, {0x80e9d00, [], 0}, 8) = 0
rt_sigaction(SIGTTIN, {0x80e9d00, [], 0}, {SIG_IGN, [], 0}, 8) = 0
rt_sigaction(SIGTTIN, {SIG_IGN, [], 0}, {0x80e9d00, [], 0}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigaction(SIGWINCH, {0x80e9550, [], SA_RESTART}, {0x80a09e0, [], 0}, 8) = 0
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
write(2, "\33]0;braiam@bt: ~\7\33[01;31mbraiam@bt\33[00m:\33[01;34m~\33[00m$ ", 56) = 56
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
read(0,  <unfinished ...>

So, according to this, there is not problem. Then, I open another non-login shell, and no joy. The history isn't loaded. A cat .bash_history reveals that the file was indeed filled but the non-login shell doesn't take it.

Now, I tried both strace -o /tmp/e -s 512 bash here (too long for character limit) and strace -o /tmp/e -s 512 gnome-terminal here (both from pastebin.com, sorry). Here with the original settings (minus the -w permission on .bash_history).

I tried login next, Ctrl + Alt + F1, logged in, pressed the up arrow, crossed fingers and it worked! But, that still leave me with the interrogant, why doesn't the non-login shell loads the history?

Best Answer

you tried history -c && history -w ?

history -c clear the cache of history function and history -w write the commands on the cache of history function (nothing) in .bash_history.

Another option is clear the bash history /dev/null > ~/.bash_history and link ~/.bash_history to /dev/null: ln -sf /dev/null ~/.bash_history

if you don't want to save the commands of the current shell session, you must run history -r to reset the history cache to its initial state (before starting session). Then you log out and the commands on history cache (the same as before starting shell session) will be written in .bash_history

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Bash OSX – Why Are Interactive Shells on OSX Login Shells by Default

The way it's supposed work is that, at the point when you get a shell prompt, both .profile and .bashrc have been run. The specific details of how you get to that point are of secondary relevance, but if either of the files didn't get run at all, you'd have a shell with incomplete settings.

The reason terminal emulators on Linux (and other X-based systems) don't need to run .profile themselves is that it will normally have been run already when you logged in to X. The settings in .profile are supposed to be of the kind that can be inherited by subprocesses, so as long as it's executed once when you log in (e.g. via .Xsession), any further subshells don't need to re-run it.

As the Debian wiki page linked by Alan Shutko explains:

"Why is .bashrc a separate file from .bash_profile, then? This is done for mostly historical reasons, when machines were extremely slow compared to today's workstations. Processing the commands in .profile or .bash_profile could take quite a long time, especially on a machine where a lot of the work had to be done by external commands (pre-bash). So the difficult initial set-up commands, which create environment variables that can be passed down to child processes, are put in .bash_profile. The transient settings and aliases which are not inherited are put in .bashrc so that they can be re-read by every subshell."

All the same rules hold on OSX, too, except for one thing — the OSX GUI doesn't run .profile when you log in, apparently because it has its own method of loading global settings. But that means that a terminal emulator on OSX does need to run .profile (by telling the shell it launches that it's a login shell), otherwise you'd end up with a potentially crippled shell.

Now, a kind of a silly peculiarity of bash, not shared by most other shells, is that it will not automatically run .bashrc if it's started as a login shell. The standard work-around for that is to include something like the following commands in .bash_profile:

[[ -e ~/.profile ]] && source ~/.profile    # load generic profile settings
[[ -e ~/.bashrc  ]] && source ~/.bashrc     # load aliases etc.

Alternatively, it's possible to have no .bash_profile at all, and just include some bash-specific code in the generic .profile file to run .bashrc if needed.

If the OSX default .bash_profile or .profile doesn't do this, then that's arguably a bug. In any case, the proper work-around is to simply add those lines to .bash_profile.

Edit: As strugee notes, the default shell on OSX used to be tcsh, whose behavior is much saner in this respect: when run as an interactive login shell, tcsh automatically reads both .profile and .tcshrc / .cshrc, and thus does not need any workarounds like the .bash_profile trick shown above.

Based on this, I'm 99% sure that the failure of OSX to supply an appropriate default .bash_profile is because, when they switched from tcsh to bash, the folks at Apple simply didn't notice this little wart in bash's startup behavior. With tcsh, no such tricks were needed — starting tcsh as a login shell from an OSX terminal emulator Just Plain Works and does the right thing without such kluges.

Bash – Why does path-completion in bash not always work

Linux autocompletions work with complete.

 ]➬complete -p  cmake
 complete -F _cmake cmake

So _cmake is in charge.

]➬type _cmake > cmake.sh

And now just see/debug it. You modify in for example _cmake_mine and call to test it:

. cmake.sh
complete -F _cmake_mine cmake

To get help for any builtin bash command:

 help complete
 help [[
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Best Answer

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Bash OSX – Why Are Interactive Shells on OSX Login Shells by Default

Bash – Why does path-completion in bash not always work

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