how to make scheduler backup command history every restart ?
i try with
crontab -e
@reboot history > backup.txt
and I reboot my pc there is a file backup.txt in directory but the file is empty, there are no results of the command history
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3 Answers
First thanks for answer
Before see answer i found the solution
crontab -e
@reboot cp /home/username/.bash_history /home/username/History_Command.txt
And it works
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1I advise perform this checking before replace the history file to avoid backup the truncated history file if something went wrong. (adjust 10000 to your current total lines, and also <username> and pls_check_bash_history path):
SHELL=/bin/bash@reboot if [[ $(wc -l </home/<username>/.bash_history) -ge 10000 ]]; then cp /home/<username>/.bash_history /home/<username>/.bash_history_reboot_bk; else echo $(wc -l </home/<username>/.bash_history) > /home/<username>/Downloads/pls_check_bash_history; fi– 林果皞Nov 16, 2017 at 10:37 -
Worth adding
--backupoption to the previous comment script to avoid truncated history issue.– LMCMay 12, 2021 at 17:56
Since the history is just a file, you could simply copy it:
SHELL=/bin/sh
PATH=/usr/bin:/bin:/usr/sbin:/sbin
@reboot cp $HOME/.bash_history $HOME/backup.txt 2>&1
Bash's history doesn't work that way. Read this link for more information.
A direct quote from the link above:
Bash maintains the list of commands internally in memory while it's running.
Since Bash is not running after a reboot, you get no output.
Furthermore, cron does not use the same PATH as your Bash shell does. More on that here.
answered Nov 13, 2016 at 16:30
