blob: 3362294983a2361c4f09fde49ba95c66a0177653 [file] [log] [blame]
history - GNU History Library
The GNU History Library is Copyright (C) 1989-2002 by the Free Software
Foundation, Inc.
Many programs read input from the user a line at a time. The GNU His-
tory library is able to keep track of those lines, associate arbitrary
data with each line, and utilize information from previous lines in
composing new ones.
The history library supports a history expansion feature that is iden-
tical to the history expansion in bbaasshh.. This section describes what
syntax features are available.
History expansions introduce words from the history list into the input
stream, making it easy to repeat commands, insert the arguments to a
previous command into the current input line, or fix errors in previous
commands quickly.
History expansion is usually performed immediately after a complete
line is read. It takes place in two parts. The first is to determine
which line from the history list to use during substitution. The sec-
ond is to select portions of that line for inclusion into the current
one. The line selected from the history is the _e_v_e_n_t, and the portions
of that line that are acted upon are _w_o_r_d_s. Various _m_o_d_i_f_i_e_r_s are
available to manipulate the selected words. The line is broken into
words in the same fashion as bbaasshh does when reading input, so that sev-
eral words that would otherwise be separated are considered one word
when surrounded by quotes (see the description of hhiissttoorryy__ttookkeenniizzee(())
below). History expansions are introduced by the appearance of the
history expansion character, which is !! by default. Only backslash (\\)
and single quotes can quote the history expansion character.
EEvveenntt DDeessiiggnnaattoorrss
An event designator is a reference to a command line entry in the his-
tory list.
!! Start a history substitution, except when followed by a bbllaannkk,
newline, = or (.
!!_n Refer to command line _n.
!!--_n Refer to the current command line minus _n.
!!!! Refer to the previous command. This is a synonym for `!-1'.
Refer to the most recent command starting with _s_t_r_i_n_g.
Refer to the most recent command containing _s_t_r_i_n_g. The trail-
ing ?? may be omitted if _s_t_r_i_n_g is followed immediately by a new-
Quick substitution. Repeat the last command, replacing _s_t_r_i_n_g_1
with _s_t_r_i_n_g_2. Equivalent to ``!!:s/_s_t_r_i_n_g_1/_s_t_r_i_n_g_2/'' (see MMoodd--
iiffiieerrss below).
!!## The entire command line typed so far.
WWoorrdd DDeessiiggnnaattoorrss
Word designators are used to select desired words from the event. A ::
separates the event specification from the word designator. It may be
omitted if the word designator begins with a ^^, $$, **, --, or %%. Words
are numbered from the beginning of the line, with the first word being
denoted by 0 (zero). Words are inserted into the current line sepa-
rated by single spaces.
00 ((zzeerroo))
The zeroth word. For the shell, this is the command word.
_n The _nth word.
^^ The first argument. That is, word 1.
$$ The last argument.
%% The word matched by the most recent `?_s_t_r_i_n_g?' search.
_x--_y A range of words; `-_y' abbreviates `0-_y'.
** All of the words but the zeroth. This is a synonym for `_1_-_$'.
It is not an error to use ** if there is just one word in the
event; the empty string is returned in that case.
xx** Abbreviates _x_-_$.
xx-- Abbreviates _x_-_$ like xx**, but omits the last word.
If a word designator is supplied without an event specification, the
previous command is used as the event.
After the optional word designator, there may appear a sequence of one
or more of the following modifiers, each preceded by a `:'.
hh Remove a trailing file name component, leaving only the head.
tt Remove all leading file name components, leaving the tail.
rr Remove a trailing suffix of the form _._x_x_x, leaving the basename.
ee Remove all but the trailing suffix.
pp Print the new command but do not execute it.
qq Quote the substituted words, escaping further substitutions.
xx Quote the substituted words as with qq, but break into words at
bbllaannkkss and newlines.
Substitute _n_e_w for the first occurrence of _o_l_d in the event
line. Any delimiter can be used in place of /. The final
delimiter is optional if it is the last character of the event
line. The delimiter may be quoted in _o_l_d and _n_e_w with a single
backslash. If & appears in _n_e_w, it is replaced by _o_l_d. A sin-
gle backslash will quote the &. If _o_l_d is null, it is set to
the last _o_l_d substituted, or, if no previous history substitu-
tions took place, the last _s_t_r_i_n_g in a !!??_s_t_r_i_n_g[[??]] search.
&& Repeat the previous substitution.
gg Cause changes to be applied over the entire event line. This is
used in conjunction with `::ss' (e.g., `::ggss//_o_l_d//_n_e_w//') or `::&&'.
If used with `::ss', any delimiter can be used in place of /, and
the final delimiter is optional if it is the last character of
the event line. An aa may be used as a synonym for gg.
GG Apply the following `ss' modifier once to each word in the event
This section describes how to use the History library in other pro-
IInnttrroodduuccttiioonn ttoo HHiissttoorryy
The programmer using the History library has available functions for
remembering lines on a history list, associating arbitrary data with a
line, removing lines from the list, searching through the list for a
line containing an arbitrary text string, and referencing any line in
the list directly. In addition, a history _e_x_p_a_n_s_i_o_n function is avail-
able which provides for a consistent user interface across different
The user using programs written with the History library has the bene-
fit of a consistent user interface with a set of well-known commands
for manipulating the text of previous lines and using that text in new
commands. The basic history manipulation commands are identical to the
history substitution provided by bbaasshh.
If the programmer desires, he can use the Readline library, which
includes some history manipulation by default, and has the added advan-
tage of command line editing.
Before declaring any functions using any functionality the History
library provides in other code, an application writer should include
the file _<_r_e_a_d_l_i_n_e_/_h_i_s_t_o_r_y_._h_> in any file that uses the History
library's features. It supplies extern declarations for all of the
library's public functions and variables, and declares all of the pub-
lic data structures.
HHiissttoorryy SSttoorraaggee
The history list is an array of history entries. A history entry is
declared as follows:
_t_y_p_e_d_e_f _v_o_i_d _* hhiissttddaattaa__tt;;
typedef struct _hist_entry {
char *line;
char *timestamp;
histdata_t data;
The history list itself might therefore be declared as
_H_I_S_T___E_N_T_R_Y _*_* tthhee__hhiissttoorryy__lliisstt;;
The state of the History library is encapsulated into a single struc-
* A structure used to pass around the current state of the history.
typedef struct _hist_state {
HIST_ENTRY **entries; /* Pointer to the entries themselves. */
int offset; /* The location pointer within this array. */
int length; /* Number of elements within this array. */
int size; /* Number of slots allocated to this array. */
int flags;
If the flags member includes HHSS__SSTTIIFFLLEEDD, the history has been stifled.
HHiissttoorryy FFuunnccttiioonnss
This section describes the calling sequence for the various functions
exported by the GNU History library.
IInniittiiaalliizziinngg HHiissttoorryy aanndd SSttaattee MMaannaaggeemmeenntt
This section describes functions used to initialize and manage the
state of the History library when you want to use the history functions
in your program.
_v_o_i_d uussiinngg__hhiissttoorryy (_v_o_i_d)
Begin a session in which the history functions might be used. This
initializes the interactive variables.
_H_I_S_T_O_R_Y___S_T_A_T_E _* hhiissttoorryy__ggeett__hhiissttoorryy__ssttaattee (_v_o_i_d)
Return a structure describing the current state of the input history.
_v_o_i_d hhiissttoorryy__sseett__hhiissttoorryy__ssttaattee (_H_I_S_T_O_R_Y___S_T_A_T_E _*_s_t_a_t_e)
Set the state of the history list according to _s_t_a_t_e.
HHiissttoorryy LLiisstt MMaannaaggeemmeenntt
These functions manage individual entries on the history list, or set
parameters managing the list itself.
_v_o_i_d aadddd__hhiissttoorryy (_c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g)
Place _s_t_r_i_n_g at the end of the history list. The associated data field
(if any) is set to NNUULLLL.
_v_o_i_d aadddd__hhiissttoorryy__ttiimmee (_c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g)
Change the time stamp associated with the most recent history entry to
_H_I_S_T___E_N_T_R_Y _* rreemmoovvee__hhiissttoorryy (_i_n_t _w_h_i_c_h)
Remove history entry at offset _w_h_i_c_h from the history. The removed
element is returned so you can free the line, data, and containing
_h_i_s_t_d_a_t_a___t ffrreeee__hhiissttoorryy__eennttrryy (_H_I_S_T___E_N_T_R_Y _*_h_i_s_t_e_n_t)
Free the history entry _h_i_s_t_e_n_t and any history library private data
associated with it. Returns the application-specific data so the
caller can dispose of it.
_H_I_S_T___E_N_T_R_Y _* rreeppllaaccee__hhiissttoorryy__eennttrryy (_i_n_t _w_h_i_c_h_, _c_o_n_s_t _c_h_a_r _*_l_i_n_e_, _h_i_s_t_-
_d_a_t_a___t _d_a_t_a)
Make the history entry at offset _w_h_i_c_h have _l_i_n_e and _d_a_t_a. This
returns the old entry so the caller can dispose of any application-spe-
cific data. In the case of an invalid _w_h_i_c_h, a NNUULLLL pointer is
_v_o_i_d cclleeaarr__hhiissttoorryy (_v_o_i_d)
Clear the history list by deleting all the entries.
_v_o_i_d ssttiiffllee__hhiissttoorryy (_i_n_t _m_a_x)
Stifle the history list, remembering only the last _m_a_x entries.
_i_n_t uunnssttiiffllee__hhiissttoorryy (_v_o_i_d)
Stop stifling the history. This returns the previously-set maximum
number of history entries (as set by ssttiiffllee__hhiissttoorryy(())). history was
stifled. The value is positive if the history was stifled, negative if
it wasn't.
_i_n_t hhiissttoorryy__iiss__ssttiifflleedd (_v_o_i_d)
Returns non-zero if the history is stifled, zero if it is not.
IInnffoorrmmaattiioonn AAbboouutt tthhee HHiissttoorryy LLiisstt
These functions return information about the entire history list or
individual list entries.
_H_I_S_T___E_N_T_R_Y _*_* hhiissttoorryy__lliisstt (_v_o_i_d)
Return a NNUULLLL terminated array of _H_I_S_T___E_N_T_R_Y _* which is the current
input history. Element 0 of this list is the beginning of time. If
there is no history, return NNUULLLL.
_i_n_t wwhheerree__hhiissttoorryy (_v_o_i_d)
Returns the offset of the current history element.
_H_I_S_T___E_N_T_R_Y _* ccuurrrreenntt__hhiissttoorryy (_v_o_i_d)
Return the history entry at the current position, as determined by
wwhheerree__hhiissttoorryy(()). If there is no entry there, return a NNUULLLL pointer.
_H_I_S_T___E_N_T_R_Y _* hhiissttoorryy__ggeett (_i_n_t _o_f_f_s_e_t)
Return the history entry at position _o_f_f_s_e_t, starting from hhiiss--
ttoorryy__bbaassee. If there is no entry there, or if _o_f_f_s_e_t is greater than
the history length, return a NNUULLLL pointer.
_t_i_m_e___t hhiissttoorryy__ggeett__ttiimmee (_H_I_S_T___E_N_T_R_Y _*)
Return the time stamp associated with the history entry passed as the
_i_n_t hhiissttoorryy__ttoottaall__bbyytteess (_v_o_i_d)
Return the number of bytes that the primary history entries are using.
This function returns the sum of the lengths of all the lines in the
MMoovviinngg AArroouunndd tthhee HHiissttoorryy LLiisstt
These functions allow the current index into the history list to be set
or changed.
_i_n_t hhiissttoorryy__sseett__ppooss (_i_n_t _p_o_s)
Set the current history offset to _p_o_s, an absolute index into the list.
Returns 1 on success, 0 if _p_o_s is less than zero or greater than the
number of history entries.
_H_I_S_T___E_N_T_R_Y _* pprreevviioouuss__hhiissttoorryy (_v_o_i_d)
Back up the current history offset to the previous history entry, and
return a pointer to that entry. If there is no previous entry, return
a NNUULLLL pointer.
_H_I_S_T___E_N_T_R_Y _* nneexxtt__hhiissttoorryy (_v_o_i_d)
Move the current history offset forward to the next history entry, and
return the a pointer to that entry. If there is no next entry, return
a NNUULLLL pointer.
SSeeaarrcchhiinngg tthhee HHiissttoorryy LLiisstt
These functions allow searching of the history list for entries con-
taining a specific string. Searching may be performed both forward and
backward from the current history position. The search may be
_a_n_c_h_o_r_e_d, meaning that the string must match at the beginning of the
history entry.
_i_n_t hhiissttoorryy__sseeaarrcchh (_c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g_, _i_n_t _d_i_r_e_c_t_i_o_n)
Search the history for _s_t_r_i_n_g, starting at the current history offset.
If _d_i_r_e_c_t_i_o_n is less than 0, then the search is through previous
entries, otherwise through subsequent entries. If _s_t_r_i_n_g is found,
then the current history index is set to that history entry, and the
value returned is the offset in the line of the entry where _s_t_r_i_n_g was
found. Otherwise, nothing is changed, and a -1 is returned.
_i_n_t hhiissttoorryy__sseeaarrcchh__pprreeffiixx (_c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g_, _i_n_t _d_i_r_e_c_t_i_o_n)
Search the history for _s_t_r_i_n_g, starting at the current history offset.
The search is anchored: matching lines must begin with _s_t_r_i_n_g. If
_d_i_r_e_c_t_i_o_n is less than 0, then the search is through previous entries,
otherwise through subsequent entries. If _s_t_r_i_n_g is found, then the
current history index is set to that entry, and the return value is 0.
Otherwise, nothing is changed, and a -1 is returned.
_i_n_t hhiissttoorryy__sseeaarrcchh__ppooss (_c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g_, _i_n_t _d_i_r_e_c_t_i_o_n_, _i_n_t _p_o_s)
Search for _s_t_r_i_n_g in the history list, starting at _p_o_s, an absolute
index into the list. If _d_i_r_e_c_t_i_o_n is negative, the search proceeds
backward from _p_o_s, otherwise forward. Returns the absolute index of
the history element where _s_t_r_i_n_g was found, or -1 otherwise.
MMaannaaggiinngg tthhee HHiissttoorryy FFiillee
The History library can read the history from and write it to a file.
This section documents the functions for managing a history file.
_i_n_t rreeaadd__hhiissttoorryy (_c_o_n_s_t _c_h_a_r _*_f_i_l_e_n_a_m_e)
Add the contents of _f_i_l_e_n_a_m_e to the history list, a line at a time. If
_f_i_l_e_n_a_m_e is NNUULLLL, then read from _~_/_._h_i_s_t_o_r_y. Returns 0 if successful,
or eerrrrnnoo if not.
_i_n_t rreeaadd__hhiissttoorryy__rraannggee (_c_o_n_s_t _c_h_a_r _*_f_i_l_e_n_a_m_e_, _i_n_t _f_r_o_m_, _i_n_t _t_o)
Read a range of lines from _f_i_l_e_n_a_m_e, adding them to the history list.
Start reading at line _f_r_o_m and end at _t_o. If _f_r_o_m is zero, start at
the beginning. If _t_o is less than _f_r_o_m, then read until the end of the
file. If _f_i_l_e_n_a_m_e is NNUULLLL, then read from _~_/_._h_i_s_t_o_r_y. Returns 0 if
successful, or eerrrrnnoo if not.
_i_n_t wwrriittee__hhiissttoorryy (_c_o_n_s_t _c_h_a_r _*_f_i_l_e_n_a_m_e)
Write the current history to _f_i_l_e_n_a_m_e, overwriting _f_i_l_e_n_a_m_e if neces-
sary. If _f_i_l_e_n_a_m_e is NNUULLLL, then write the history list to _~_/_._h_i_s_t_o_r_y.
Returns 0 on success, or eerrrrnnoo on a read or write error.
_i_n_t aappppeenndd__hhiissttoorryy (_i_n_t _n_e_l_e_m_e_n_t_s_, _c_o_n_s_t _c_h_a_r _*_f_i_l_e_n_a_m_e)
Append the last _n_e_l_e_m_e_n_t_s of the history list to _f_i_l_e_n_a_m_e. If _f_i_l_e_n_a_m_e
is NNUULLLL, then append to _~_/_._h_i_s_t_o_r_y. Returns 0 on success, or eerrrrnnoo on
a read or write error.
_i_n_t hhiissttoorryy__ttrruunnccaattee__ffiillee (_c_o_n_s_t _c_h_a_r _*_f_i_l_e_n_a_m_e_, _i_n_t _n_l_i_n_e_s)
Truncate the history file _f_i_l_e_n_a_m_e, leaving only the last _n_l_i_n_e_s lines.
If _f_i_l_e_n_a_m_e is NNUULLLL, then _~_/_._h_i_s_t_o_r_y is truncated. Returns 0 on suc-
cess, or eerrrrnnoo on failure.
HHiissttoorryy EExxppaannssiioonn
These functions implement history expansion.
_i_n_t hhiissttoorryy__eexxppaanndd (_c_h_a_r _*_s_t_r_i_n_g_, _c_h_a_r _*_*_o_u_t_p_u_t)
Expand _s_t_r_i_n_g, placing the result into _o_u_t_p_u_t, a pointer to a string.
0 If no expansions took place (or, if the only change in
the text was the removal of escape characters preceding
the history expansion character);
1 if expansions did take place;
-1 if there was an error in expansion;
2 if the returned line should be displayed, but not exe-
cuted, as with the ::pp modifier.
If an error ocurred in expansion, then _o_u_t_p_u_t contains a descriptive
error message.
_c_h_a_r _* ggeett__hhiissttoorryy__eevveenntt (_c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g_, _i_n_t _*_c_i_n_d_e_x_, _i_n_t _q_c_h_a_r)
Returns the text of the history event beginning at _s_t_r_i_n_g + _*_c_i_n_d_e_x.
_*_c_i_n_d_e_x is modified to point to after the event specifier. At function
entry, _c_i_n_d_e_x points to the index into _s_t_r_i_n_g where the history event
specification begins. _q_c_h_a_r is a character that is allowed to end the
event specification in addition to the ``normal'' terminating charac-
_c_h_a_r _*_* hhiissttoorryy__ttookkeenniizzee (_c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g)
Return an array of tokens parsed out of _s_t_r_i_n_g, much as the shell
might. The tokens are split on the characters in the hhiiss--
ttoorryy__wwoorrdd__ddeelliimmiitteerrss variable, and shell quoting conventions are
_c_h_a_r _* hhiissttoorryy__aarrgg__eexxttrraacctt (_i_n_t _f_i_r_s_t_, _i_n_t _l_a_s_t_, _c_o_n_s_t _c_h_a_r _*_s_t_r_i_n_g)
Extract a string segment consisting of the _f_i_r_s_t through _l_a_s_t arguments
present in _s_t_r_i_n_g. Arguments are split using hhiissttoorryy__ttookkeenniizzee(()).
HHiissttoorryy VVaarriiaabblleess
This section describes the externally-visible variables exported by the
GNU History Library.
_i_n_t hhiissttoorryy__bbaassee
The logical offset of the first entry in the history list.
_i_n_t hhiissttoorryy__lleennggtthh
The number of entries currently stored in the history list.
_i_n_t hhiissttoorryy__mmaaxx__eennttrriieess
The maximum number of history entries. This must be changed using ssttii--
_i_n_t hhiissttoorryy__wwrriittee__ttiimmeessttaammppss
If non-zero, timestamps are written to the history file, so they can be
preserved between sessions. The default value is 0, meaning that
timestamps are not saved.
_c_h_a_r hhiissttoorryy__eexxppaannssiioonn__cchhaarr
The character that introduces a history event. The default is !!. Set-
ting this to 0 inhibits history expansion.
_c_h_a_r hhiissttoorryy__ssuubbsstt__cchhaarr
The character that invokes word substitution if found at the start of a
line. The default is ^^.
_c_h_a_r hhiissttoorryy__ccoommmmeenntt__cchhaarr
During tokenization, if this character is seen as the first character
of a word, then it and all subsequent characters up to a newline are
ignored, suppressing history expansion for the remainder of the line.
This is disabled by default.
_c_h_a_r _* hhiissttoorryy__wwoorrdd__ddeelliimmiitteerrss
The characters that separate tokens for hhiissttoorryy__ttookkeenniizzee(()). The
default value is "" \\tt\\nn(())<<>>;;&&||"".
_c_h_a_r _* hhiissttoorryy__nnoo__eexxppaanndd__cchhaarrss
The list of characters which inhibit history expansion if found immedi-
ately following hhiissttoorryy__eexxppaannssiioonn__cchhaarr. The default is space, tab,
newline, \\rr, and ==.
_c_h_a_r _* hhiissttoorryy__sseeaarrcchh__ddeelliimmiitteerr__cchhaarrss
The list of additional characters which can delimit a history search
string, in addition to space, tab, _: and _? in the case of a substring
search. The default is empty.
_i_n_t hhiissttoorryy__qquuootteess__iinnhhiibbiitt__eexxppaannssiioonn
If non-zero, single-quoted words are not scanned for the history expan-
sion character. The default value is 0.
_r_l___l_i_n_e_b_u_f___f_u_n_c___t _* hhiissttoorryy__iinnhhiibbiitt__eexxppaannssiioonn__ffuunnccttiioonn
This should be set to the address of a function that takes two argu-
ments: a cchhaarr ** (_s_t_r_i_n_g) and an iinntt index into that string (_i). It
should return a non-zero value if the history expansion starting at
_s_t_r_i_n_g_[_i_] should not be performed; zero if the expansion should be
done. It is intended for use by applications like bbaasshh that use the
history expansion character for additional purposes. By default, this
variable is set to NNUULLLL.
Default filename for reading and writing saved history
_T_h_e _G_n_u _R_e_a_d_l_i_n_e _L_i_b_r_a_r_y, Brian Fox and Chet Ramey
_T_h_e _G_n_u _H_i_s_t_o_r_y _L_i_b_r_a_r_y, Brian Fox and Chet Ramey
Brian Fox, Free Software Foundation
Chet Ramey, Case Western Reserve University
If you find a bug in the hhiissttoorryy library, you should report it. But
first, you should make sure that it really is a bug, and that it
appears in the latest version of the hhiissttoorryy library that you have.
Once you have determined that a bug actually exists, mail a bug report
to _b_u_g_-_r_e_a_d_l_i_n_e@_g_n_u_._o_r_g. If you have a fix, you are welcome to mail
that as well! Suggestions and `philosophical' bug reports may be
mailed to _b_u_g_-_r_e_a_d_l_i_n_e@_g_n_u_._o_r_g or posted to the Usenet newsgroup
Comments and bug reports concerning this manual page should be directed
to _c_h_e_t_@_i_n_s_._C_W_R_U_._E_d_u.
GNU History 5.0 2003 July 31 HISTORY(3)