# Null bytes in repl\_history on shared home directory

**URL:** <https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471>\
**Category:** General Usage\
**Created:** [July 3, 2020, 12:25pm UTC](https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471 "2020-07-03T12:25:37Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![lhupe](https://avatars.discourse-cdn.com/v4/letter/l/9fc348/32.png) [@lhupe](https://discourse.julialang.org/u/lhupe)\
**Post date:** [July 3, 2020, 12:25pm UTC](https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471/1 "2020-07-03T12:25:37Z")

</div>

I’m currently using julia on a network of computers with shared home directories. I’ve noticed that when I open REPLs on two machines simultaneously, the `repl_history.jl` file gets corrupted and I get this error message the next time I start a REPL

> **Click for full error message**
>
> ```julia
> ERROR: Invalid history file (/home/lhupe/.julia/logs/repl_history.jl) format:
> If you have a history file left over from an older version of Julia,
> try renaming or deleting it.
> Invalid character: '\0' at line 7
> Stacktrace:
> [1] error(::String, ::String, ::String, ::Int64) at ./error.jl:42
> [2] hist_from_file(::Any, ::Any, ::Any) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/REPL/src/REPL.jl:434
> [3] setup_interface(::REPL.LineEditREPL, ::Bool, ::Any) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/REPL/src/REPL.jl:874
> [4] setup_interface(::REPL.LineEditREPL; hascolor::Bool, extra_repl_keymap::Any) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/REPL/src/REPL.jl:779
> [5] setup_interface at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/REPL/src/REPL.jl:779 [inlined]
> [6] (::Pkg.var"#1#2")(::REPL.LineEditREPL) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/Pkg/src/Pkg.jl:519
> [7] __atreplinit(::REPL.LineEditREPL) at ./client.jl:339
> [8] #invokelatest#1 at ./essentials.jl:712 [inlined]
> [9] invokelatest at ./essentials.jl:711 [inlined]
> [10] _atreplinit at ./client.jl:346 [inlined]
> [11] (::Base.var"#764#766"{Bool,Bool,Bool,Bool})(::Module) at ./client.jl:382
> [12] #invokelatest#1 at ./essentials.jl:712 [inlined]
> [13] invokelatest at ./essentials.jl:711 [inlined]
> [14] run_main_repl(::Bool, ::Bool, ::Bool, ::Bool, ::Bool) at ./client.jl:367
> [15] exec_options(::Base.JLOptions) at ./client.jl:305
> [16] _start() at ./client.jl:484
> 
> [ Info: Disabling history file for this session
> 
> ```

This is apparently independent of what I do during the simulatenous REPL sessions; I can reproduce the bug by immediately closing the REPLs after opening them. As soon as there are two sessions running at the same time on different hosts, the history file gets corrupted.

Does anybody else have this problem or know how to fix it?

---

<div class="post-metadata">

**Author:** ![lhupe](https://avatars.discourse-cdn.com/v4/letter/l/9fc348/32.png) [@lhupe](https://discourse.julialang.org/u/lhupe)\
**Post date:** [July 23, 2020, 7:17am UTC](https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471/2 "2020-07-23T07:17:56Z")

</div>

For a detailed example: [https://github.com/JuliaLang/julia/issues/36707](https://github.com/JuliaLang/julia/issues/36707)

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<div class="post-metadata">

**Author:** ![monty](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/monty/32/44234_2.png) [@monty](https://discourse.julialang.org/u/monty)\
**Post date:** [August 26, 2020, 7:09pm UTC](https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471/3 "2020-08-26T19:09:45Z")

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here is a simple script to fix:

```julia
egrep "^(#|\t)" ~/.julia/logs/repl_history.jl > ~/.julia/logs/repl_history_fix.jl
mv ~/.julia/logs/repl_history.jl ~/.julia/logs/repl_history_old.jl
mv ~/.julia/logs/repl_history_fix.jl ~/.julia/logs/repl_history.jl

```

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<div class="post-metadata">

**Author:** ![lhupe](https://avatars.discourse-cdn.com/v4/letter/l/9fc348/32.png) [@lhupe](https://discourse.julialang.org/u/lhupe)\
**Post date:** [August 26, 2020, 7:43pm UTC](https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471/4 "2020-08-26T19:43:56Z")

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Thanks for your response!  
Your workaround has one tiny issue: If `grep` (and thus also egrep) finds null bytes within the first few bytes of a file, it will interpret it as a binary file (and thus not function as expected). In order to prevent this, you can force interpreting the file as text using the `-a` flag.  
Also – on my system – for some reason, `egrep` doesn’t match the tab characters (ASCII `0x09`) (which is probably due to an error on my side, I don’t have time to check now). If anyone else comes accross this problem, I’d suggest changing `\t` to a more generic `\s` to match all whitespace (which strangely enough works for me)

Additionally, I have since come up with my own workaround, which I forgot to post here. Using `sed`, one can remove the null bytes in place

```julia
sed -i 's/\x0//g' ~/.julia/logs/repl_history.jl

```

* * *

Still, both our solutions are only crude workarounds. I often have REPLs running on multiple machines using the same NFS home directory, and cleaning up the REPL history every few hours slightly impairs my workflow.  
However, there is hope – [another issue](https://github.com/JuliaLang/julia/issues/37015) on this problem was recently opened, and it seems to be less dead than mine.