| savehistory {utils} | R Documentation |
Load or save or display the commands history.
loadhistory(file = ".Rhistory")
savehistory(file = ".Rhistory")
history(max.show = 25, reverse = FALSE, pattern, ...)
timestamp(stamp = date(),
prefix = "##------ ", suffix = " ------##",
quiet = FALSE)
file |
The name of the file in which to save the history, or from which to load it. The path is relative to the current working directory. |
max.show |
The maximum number of lines to show. Inf will
give all of the currently available history. |
reverse |
logical. If true, the lines are shown in reverse order. Note: this is not useful when there are continuation lines. |
pattern |
A character string to be matched against the lines of the history |
... |
Arguments to be passed to grep when doing
the matching. |
stamp |
A value or vector of values to be written into the history. |
prefix |
A prefix to apply to each line. |
suffix |
A suffix to apply to each line. |
quiet |
If TRUE, suppress printing timestamp to the console. |
There are several history mechanisms available for the different R
consoles, which work in similar but not identical ways. Other uses of
R, in particular embedded uses, may have no history.
This works under the readline and GNOME and MacOS X consoles,
but not otherwise (for example, in batch use or in an embedded application).
The readline history mechanism is controlled by two environment
variables: R_HISTSIZE controls the number of lines that are
saved (default 512), and R_HISTFILE sets the filename used for
the loading/saving of history if requested at the beginning/end of a
session (but not the default for these functions). There is no limit
on the number of lines of history retained during a session, so
setting R_HISTSIZE to a large value has no penalty unless a
large file is actually generated.
These variables are read at the time of saving, so can be altered
within a session by the use of Sys.setenv.
history shows only unique matching lines if pattern is
supplied.
The timestamp function writes a timestamp (or other message)
into the history and echos it to the console. On platforms that do not
support a history mechanism (where the mechanism does not yet support
timestamps) only the console message is printed.
If you want to save the history (almost) every session, you can put a
call to savehistory() in .Last. See the examples.
## Not run:
.Last <- function()
if(interactive()) try(savehistory("~/.Rhistory"))
## End(Not run)