Age | Commit message (Collapse) | Author |
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This patch adds a mechanism by which shell history gets stored
persistently on disk and gets loaded whenever a new shell session
begins.
The log files are added to the user's cache directory, with multiple
files in it, although the location is configurable.
All Erlang instances on a given host will share the same log file.
There are two hook points in group.erl that are used: when instantiating
the buffer, where we fetch from disk, and when adding a line to the
buffer (gets stored).
This allows all shell instances to use the same base set of lines when
loaded, but to keep their history separate after the fact. As lines are
added as you go, a new shell session (with ^G -> s -> c) will have
access to previous sessions' lines.
The implementation makes use of the disk_log library with a rotating log
in order to store data, and allow automated repairs.
By default, the feature is disabled and must be turned on through OTP
environment variable part of the kernel application. The options
include:
| Option | Accepted values | Default | Description |
| ------------------------ | ----------------- |---------- | -------------------- |
| shell_history | enabled, disabled | disabled | turn feature on/off |
| shell_history_path | any string | user cache| where to put files |
| shell_history_file_bytes | 51200..N bytes | 512kb | max data size (>50kb)|
| shell_history_drop | ["q().", ...] | [] | blacklisted lines |
A version header is added to the disk_log configuration, allowing
changes in the storage format to be enacted in the future (i.e. adding
segmentation by node name in the same file, or encoding) without
conflict.
Log rotation is used with multiple log files to ensure proper
enforcement of resizing without too much data loss. Because disk_log
does not allow to just flush bits of content on rewrite (it truncates
any full file), we instead use a wrap log and try to divide the
configured size into up to 10 log files so that every time we rotate a
log, we lose only 10% of the data. This remains true for corrupted files
that cannot fully be repaired.
This many-logs-based approach in turn forces the use of a minimal log
size for the `shell_history_file_bytes` configuration, since it has to
be divided by 10.
The shell history is not loaded for the `user` process which, despite
running the group.erl module, does not actually require history as it
mostly just forwards IO protocol information.
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Added a put_chars_sync to the protocol that can be used to
talk to user_drv and made group use it. This is needed in order
to guarantee that bytes has been pushed to the tty port when
doing something like this:
io:format("halting\n"),erlang:halt(0).
Before this change the halting message could be lost in the message
queue of the user_drv process, this is no longer possible.
This commit also fixes ssh_cli as that plugs itself in as a user_drv
process.
OTP-12240
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The documentation of some Unicode functions in io_lib was committed by
mistake.
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Search mode can be entered by pressing ctrl-r. Enter terms and press
ctrl-r again to search backwards, or ctrl-s to then search forward (if
you terminal doesn't eat up that one). Press enter to execute the line,
or use tab, arrow keys, or other control sequences (^D, ^K, etc.) to
exit search mode while remaining on the last found line. Exiting is also
possible by pressing the escape key twice.
The search mode is a simpler version of the one available in bash or
zsh shells.
This adds a few modes to the shell (search, on top of none and meta) in
group.erl for history search, and a few more in edlin.erl to change the
meaning of control sequences while searching.
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* dp/shell-line-editing:
Readline-style line edit history
OTP-8635 dp/shell-line-editing
The shell's line editing has been improved to more resemble the behaviour
of readline and other shells. (Thanks to Dave Peticolas)
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Change the shell's line buffer mechanism to more
closely match readline-based shells. New behavior:
1. Blank lines are not added to the line buffer.
2. Pressing the down arrow on the last line causes no change.
The previous behavior erased the line.
3. The new line is temporarily added to the line buffer
so the user can move to previous lines with up arrows
and then back to the new line with down arrows.
The previous behavior discarded the partially written
new line.
4. Changes made to previous lines while exploring the line
buffer history are preserved.
The previous behavior discarded changes made to older lines.
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