Merge two zsh history files

merge-zsh-history.sh

#!/bin/bash
# Inspired on https://david-kerwick.github.io/2017-01-04-combining-zsh-history-files/
set -e
history1=$1
history2=$2
merged=$3

echo "Merging history files: $history1 + $history2"

test ! -f $history1 && echo "File $history1 not found" && exit 1
test ! -f $history2 && echo "File $history2 not found" && exit 1

cat $history1 $history2 | awk -v date="WILL_NOT_APPEAR$(date +"%s")" '{if (sub(/\\$/,date)) printf "%s", $0; else print $0}' | LC_ALL=C sort -u | awk -v date="WILL_NOT_APPEAR$(date +"%s")" '{gsub('date',"\\\n"); print $0}' > $merged

echo "Merged to: $merged"

thanks!

Nice!

zsh can do this itself:

    builtin fc -R -I "$hist_file"
    builtin fc -R -I "$another_hist_file"

    # write the loaded history to HISTFILE
    builtin fc -W "$HISTFILE"

This was exactly what I needed. Thanks for sharing!

Sweet! Thanks to both of you for providing options. I went with the builtin solution and it worked great.

@NightMachinery This is great and works when I paste it to a terminal manually, however, it doesn't work for me when I create a script like merge-zhs-histories.sh. I tried this:

#!/usr/bin/env zsh

hist_file_1="/Users/borekb/.zsh_history"
hist_file_2="/Users/borekb/.zsh_history (1)"
hist_file_merged="/Users/borekb/.zsh_history-MERGED"

builtin fc -R -I "$hist_file_1"
builtin fc -R -I "$hist_file_2"

builtin fc -W "$hist_file_merged"

The .zsh_history-MERGED file is not created for me (but it is created when I copy/paste the code to my terminal).

Is that something specific about builtin fc? Or am I making some obvious mistake?

@borekb I assume these only work in an interactive shell

edit: yep: https://zsh.sourceforge.io/Doc/Release/Shell-Builtin-Commands.html

I tried the builtin fc method mentioned above but it doesn't sort the output! So in the resulting history you get all of one file first then all of the other file. Apparently zsh doesn't care that the timestamps are out of order and doesn't sort them. But the awk solution worked great for me!

Thanks, I was getting error with merge_history.sh:
awk: towc: multibyte conversion failure on: '�`|:"' ()[]{}<>\t"'

builtin worked like a charm. Thanks

Thank you!