What is the point of this? Whenever I close my shell it appends to the history file without adding this. I have never seen it overwrite my history file.
Code:
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend
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I am not 100% sure, but I "think" it is there for some legacy backward compatibility issue.
On my systems, the history is always appended even when histappend is set to off.
For example, on macOS:
Code:
Tim$ shopt
cdable_vars off
cdspell off
checkhash off
checkwinsize on
cmdhist on
compat31 off
dotglob off
execfail off
expand_aliases on
extdebug off
extglob off
extquote on
failglob off
force_fignore on
gnu_errfmt off
histappend off
histreedit off
histverify off
hostcomplete on
huponexit off
interactive_comments on
lithist off
login_shell on
mailwarn off
no_empty_cmd_completion off
nocaseglob off
nocasematch off
nullglob off
progcomp on
promptvars on
restricted_shell off
shift_verbose off
sourcepath on
xpg_echo off
Linux:
Code:
# shopt
autocd off
cdable_vars off
cdspell off
checkhash off
checkjobs off
checkwinsize on
cmdhist on
compat31 off
compat32 off
compat40 off
compat41 off
compat42 off
compat43 off
complete_fullquote on
direxpand off
dirspell off
dotglob off
execfail off
expand_aliases on
extdebug off
extglob on
extquote on
failglob off
force_fignore on
globasciiranges off
globstar off
gnu_errfmt off
histappend off
histreedit off
histverify off
hostcomplete off
huponexit off
inherit_errexit off
interactive_comments on
lastpipe off
lithist off
login_shell on
mailwarn off
no_empty_cmd_completion off
nocaseglob off
nocasematch off
nullglob off
progcomp on
promptvars on
restricted_shell off
shift_verbose off
sourcepath on
xpg_echo off
In both example cases above, the history is appended and not overwritten even though it is shown to be "off".
Location: Asia Pacific, Cyberspace, in the Dark Dystopia
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Supplementary info, from a bash-related man page:
Quote:
histappend
If set, the history list is appended to the history file when the shell exits,
rather than overwriting the history file.
shopt -s histappend
To append every line to history individually set:
PROMPT_COMMAND='history -a'
With these two settings, a new shell will get the history lines from all previous
shells instead of the default 'last window closed'>history
(the history file is named by the value of the HISTFILE variable)
in your .bashrc will mimic the behaviour of ksh in that it writes all commands to its history file as (after?) it executes them.
Presumably the correct order of history -a and history -n would allow two or more shells to share their history, exactly like ksh (my least favourite feature of ksh)
Hi,
I am using bash shell's extended pattern matching.
What tweak the following code needs in order to get the expected output?
shopt -s extglob
f="a@b@_c@d@_e"
echo "${f/@(@|@_)/__}"
My expected output is:
a__b__c__d__e
but the actual output is:
a__b@_c@d@_e
# that is, how to... (3 Replies)
Hi,
I am using BASH. In a directory there are files that match either of the following 2 patterns: *.L1A_AC* or S*.L1A_MLAC*
I would like to write a script that will include a for loop, where for each file in the directory, a certain function will be performed. For example:
for FILE in... (4 Replies)
07-21-2019
