import of readlilne 5.1

[deliverable/binutils-gdb.git] / readline / doc / history.0

HISTORY(3)                                                          HISTORY(3)



N\bNA\bAM\bME\bE
       history - GNU History Library

C\bCO\bOP\bPY\bYR\bRI\bIG\bGH\bHT\bT
       The GNU History Library is Copyright (C) 1989-2002 by the Free Software
       Foundation, Inc.

D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN
       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.


H\bHI\bIS\bST\bTO\bOR\bRY\bY E\bEX\bXP\bPA\bAN\bNS\bSI\bIO\bON\bN
       The  history library supports a history expansion feature that is iden-
       tical to the history expansion in b\bba\bas\bsh\bh.\b.  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 _\be_\bv_\be_\bn_\bt, and the portions
       of  that  line  that  are  acted upon are _\bw_\bo_\br_\bd_\bs.  Various _\bm_\bo_\bd_\bi_\bf_\bi_\be_\br_\bs are
       available to manipulate the selected words.  The line  is  broken  into
       words in the same fashion as b\bba\bas\bsh\bh 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 h\bhi\bis\bst\bto\bor\bry\by_\b_t\bto\bok\bke\ben\bni\biz\bze\be(\b()\b)
       below).  History expansions are introduced by  the  appearance  of  the
       history expansion character, which is !\b! by default.  Only backslash (\\b\)
       and single quotes can quote the history expansion character.

   E\bEv\bve\ben\bnt\bt D\bDe\bes\bsi\big\bgn\bna\bat\bto\bor\brs\bs
       An event designator is a reference to a command line entry in the  his-
       tory list.

       !\b!      Start  a  history substitution, except when followed by a b\bbl\bla\ban\bnk\bk,
              newline, = or (.
       !\b!_\bn     Refer to command line _\bn.
       !\b!-\b-_\bn    Refer to the current command line minus _\bn.
       !\b!!\b!     Refer to the previous command.  This is a synonym for `!-1'.
       !\b!_\bs_\bt_\br_\bi_\bn_\bg
              Refer to the most recent command starting with _\bs_\bt_\br_\bi_\bn_\bg.
       !\b!?\b?_\bs_\bt_\br_\bi_\bn_\bg[\b[?\b?]\b]
              Refer to the most recent command containing _\bs_\bt_\br_\bi_\bn_\bg.  The  trail-
              ing ?\b? may be omitted if _\bs_\bt_\br_\bi_\bn_\bg is followed immediately by a new-
              line.
       ^\b^_\bs_\bt_\br_\bi_\bn_\bg_\b1^\b^_\bs_\bt_\br_\bi_\bn_\bg_\b2^\b^
              Quick substitution.  Repeat the last command, replacing  _\bs_\bt_\br_\bi_\bn_\bg_\b1
              with _\bs_\bt_\br_\bi_\bn_\bg_\b2.  Equivalent to ``!!:s/_\bs_\bt_\br_\bi_\bn_\bg_\b1/_\bs_\bt_\br_\bi_\bn_\bg_\b2/'' (see M\bMo\bod\bd-\b-
              i\bif\bfi\bie\ber\brs\bs below).
       !\b!#\b#     The entire command line typed so far.

   W\bWo\bor\brd\bd D\bDe\bes\bsi\big\bgn\bna\bat\bto\bor\brs\bs
       Word designators are used to select desired words from the event.  A  :\b:
       separates  the event specification from the word designator.  It may be
       omitted if the word designator begins with a ^\b^, $\b$, *\b*, -\b-, or  %\b%.   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.

       0\b0 (\b(z\bze\ber\bro\bo)\b)
              The zeroth word.  For the shell, this is the command word.
       _\bn      The _\bnth word.
       ^\b^      The first argument.  That is, word 1.
       $\b$      The last argument.
       %\b%      The word matched by the most recent `?_\bs_\bt_\br_\bi_\bn_\bg?' search.
       _\bx-\b-_\by    A range of words; `-_\by' abbreviates `0-_\by'.
       *\b*      All  of  the words but the zeroth.  This is a synonym for `_\b1_\b-_\b$'.
              It is not an error to use *\b* if there is just  one  word  in  the
              event; the empty string is returned in that case.
       x\bx*\b*     Abbreviates _\bx_\b-_\b$.
       x\bx-\b-     Abbreviates _\bx_\b-_\b$ like x\bx*\b*, but omits the last word.

       If  a  word  designator is supplied without an event specification, the
       previous command is used as the event.

   M\bMo\bod\bdi\bif\bfi\bie\ber\brs\bs
       After the optional word designator, there may appear a sequence of  one
       or more of the following modifiers, each preceded by a `:'.

       h\bh      Remove a trailing file name component, leaving only the head.
       t\bt      Remove all leading file name components, leaving the tail.
       r\br      Remove a trailing suffix of the form _\b._\bx_\bx_\bx, leaving the basename.
       e\be      Remove all but the trailing suffix.
       p\bp      Print the new command but do not execute it.
       q\bq      Quote the substituted words, escaping further substitutions.
       x\bx      Quote the substituted words as with q\bq, but break into  words  at
              b\bbl\bla\ban\bnk\bks\bs and newlines.
       s\bs/\b/_\bo_\bl_\bd/\b/_\bn_\be_\bw/\b/
              Substitute  _\bn_\be_\bw  for  the  first  occurrence of _\bo_\bl_\bd 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 _\bo_\bl_\bd and _\bn_\be_\bw with a  single
              backslash.   If & appears in _\bn_\be_\bw, it is replaced by _\bo_\bl_\bd.  A sin-
              gle backslash will quote the &.  If _\bo_\bl_\bd is null, it  is  set  to
              the  last  _\bo_\bl_\bd substituted, or, if no previous history substitu-
              tions took place, the last _\bs_\bt_\br_\bi_\bn_\bg in a !\b!?\b?_\bs_\bt_\br_\bi_\bn_\bg[\b[?\b?]\b]  search.
       &\b&      Repeat the previous substitution.
       g\bg      Cause changes to be applied over the entire event line.  This is
              used  in  conjunction  with `:\b:s\bs' (e.g., `:\b:g\bgs\bs/\b/_\bo_\bl_\bd/\b/_\bn_\be_\bw/\b/') or `:\b:&\b&'.
              If used with `:\b:s\bs', 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 a\ba may be used as a synonym for g\bg.
       G\bG      Apply the following `s\bs' modifier once to each word in the  event
              line.

P\bPR\bRO\bOG\bGR\bRA\bAM\bMM\bMI\bIN\bNG\bG W\bWI\bIT\bTH\bH H\bHI\bIS\bST\bTO\bOR\bRY\bY F\bFU\bUN\bNC\bCT\bTI\bIO\bON\bNS\bS
       This  section  describes  how  to use the History library in other pro-
       grams.

   I\bIn\bnt\btr\bro\bod\bdu\buc\bct\bti\bio\bon\bn t\bto\bo H\bHi\bis\bst\bto\bor\bry\by
       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 _\be_\bx_\bp_\ba_\bn_\bs_\bi_\bo_\bn function is avail-
       able  which  provides  for a consistent user interface across different
       programs.

       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 b\bba\bas\bsh\bh.

       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  _\b<_\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b/_\bh_\bi_\bs_\bt_\bo_\br_\by_\b._\bh_\b>  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.


   H\bHi\bis\bst\bto\bor\bry\by S\bSt\bto\bor\bra\bag\bge\be
       The  history  list  is an array of history entries.  A history entry is
       declared as follows:

       _\bt_\by_\bp_\be_\bd_\be_\bf _\bv_\bo_\bi_\bd _\b* h\bhi\bis\bst\btd\bda\bat\bta\ba_\b_t\bt;\b;

       typedef struct _hist_entry {
         char *line;
         char *timestamp;
         histdata_t data;
       } HIST_ENTRY;

       The history list itself might therefore be declared as

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b*_\b* t\bth\bhe\be_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_l\bli\bis\bst\bt;\b;

       The state of the History library is encapsulated into a  single  struc-
       ture:

       /*
        * 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;
       } HISTORY_STATE;

       If  the flags member includes H\bHS\bS_\b_S\bST\bTI\bIF\bFL\bLE\bED\bD, the history has been stifled.

H\bHi\bis\bst\bto\bor\bry\by F\bFu\bun\bnc\bct\bti\bio\bon\bns\bs
       This section describes the calling sequence for the  various  functions
       exported by the GNU History library.

   I\bIn\bni\bit\bti\bia\bal\bli\biz\bzi\bin\bng\bg H\bHi\bis\bst\bto\bor\bry\by a\ban\bnd\bd S\bSt\bta\bat\bte\be M\bMa\ban\bna\bag\bge\bem\bme\ben\bnt\bt
       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.

       _\bv_\bo_\bi_\bd u\bus\bsi\bin\bng\bg_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bv_\bo_\bi_\bd)
       Begin  a  session  in  which the history functions might be used.  This
       initializes the interactive variables.

       _\bH_\bI_\bS_\bT_\bO_\bR_\bY_\b__\bS_\bT_\bA_\bT_\bE _\b* h\bhi\bis\bst\bto\bor\bry\by_\b_g\bge\bet\bt_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_s\bst\bta\bat\bte\be (_\bv_\bo_\bi_\bd)
       Return a structure describing the current state of the input history.

       _\bv_\bo_\bi_\bd h\bhi\bis\bst\bto\bor\bry\by_\b_s\bse\bet\bt_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_s\bst\bta\bat\bte\be (_\bH_\bI_\bS_\bT_\bO_\bR_\bY_\b__\bS_\bT_\bA_\bT_\bE _\b*_\bs_\bt_\ba_\bt_\be)
       Set the state of the history list according to _\bs_\bt_\ba_\bt_\be.


   H\bHi\bis\bst\bto\bor\bry\by L\bLi\bis\bst\bt M\bMa\ban\bna\bag\bge\bem\bme\ben\bnt\bt
       These functions manage individual entries on the history list,  or  set
       parameters managing the list itself.

       _\bv_\bo_\bi_\bd a\bad\bdd\bd_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg)
       Place _\bs_\bt_\br_\bi_\bn_\bg at the end of the history list.  The associated data field
       (if any) is set to N\bNU\bUL\bLL\bL.

       _\bv_\bo_\bi_\bd a\bad\bdd\bd_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_t\bti\bim\bme\be (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg)
       Change the time stamp associated with the most recent history entry  to
       _\bs_\bt_\br_\bi_\bn_\bg.

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b* r\bre\bem\bmo\bov\bve\be_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bi_\bn_\bt _\bw_\bh_\bi_\bc_\bh)
       Remove  history  entry  at  offset _\bw_\bh_\bi_\bc_\bh from the history.  The removed
       element is returned so you can free  the  line,  data,  and  containing
       structure.

       _\bh_\bi_\bs_\bt_\bd_\ba_\bt_\ba_\b__\bt f\bfr\bre\bee\be_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_e\ben\bnt\btr\bry\by (_\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b*_\bh_\bi_\bs_\bt_\be_\bn_\bt)
       Free  the  history  entry  _\bh_\bi_\bs_\bt_\be_\bn_\bt and any history library private data
       associated with it.   Returns  the  application-specific  data  so  the
       caller can dispose of it.

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY  _\b* r\bre\bep\bpl\bla\bac\bce\be_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_e\ben\bnt\btr\bry\by (_\bi_\bn_\bt _\bw_\bh_\bi_\bc_\bh_\b, _\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bl_\bi_\bn_\be_\b, _\bh_\bi_\bs_\bt_\b-
       _\bd_\ba_\bt_\ba_\b__\bt _\bd_\ba_\bt_\ba)
       Make the history entry at  offset  _\bw_\bh_\bi_\bc_\bh  have  _\bl_\bi_\bn_\be  and  _\bd_\ba_\bt_\ba.   This
       returns the old entry so the caller can dispose of any application-spe-
       cific data.  In the case  of  an  invalid  _\bw_\bh_\bi_\bc_\bh,  a  N\bNU\bUL\bLL\bL  pointer  is
       returned.

       _\bv_\bo_\bi_\bd c\bcl\ble\bea\bar\br_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bv_\bo_\bi_\bd)
       Clear the history list by deleting all the entries.

       _\bv_\bo_\bi_\bd s\bst\bti\bif\bfl\ble\be_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bi_\bn_\bt _\bm_\ba_\bx)
       Stifle the history list, remembering only the last _\bm_\ba_\bx entries.

       _\bi_\bn_\bt u\bun\bns\bst\bti\bif\bfl\ble\be_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bv_\bo_\bi_\bd)
       Stop  stifling  the  history.   This returns the previously-set maximum
       number of history entries (as set by  s\bst\bti\bif\bfl\ble\be_\b_h\bhi\bis\bst\bto\bor\bry\by(\b()\b)).   history  was
       stifled.  The value is positive if the history was stifled, negative if
       it wasn't.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_i\bis\bs_\b_s\bst\bti\bif\bfl\ble\bed\bd (_\bv_\bo_\bi_\bd)
       Returns non-zero if the history is stifled, zero if it is not.


   I\bIn\bnf\bfo\bor\brm\bma\bat\bti\bio\bon\bn A\bAb\bbo\bou\but\bt t\bth\bhe\be H\bHi\bis\bst\bto\bor\bry\by L\bLi\bis\bst\bt
       These functions return information about the  entire  history  list  or
       individual list entries.

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b*_\b* h\bhi\bis\bst\bto\bor\bry\by_\b_l\bli\bis\bst\bt (_\bv_\bo_\bi_\bd)
       Return  a  N\bNU\bUL\bLL\bL  terminated  array of _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b* which is the current
       input history.  Element 0 of this list is the beginning  of  time.   If
       there is no history, return N\bNU\bUL\bLL\bL.

       _\bi_\bn_\bt w\bwh\bhe\ber\bre\be_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bv_\bo_\bi_\bd)
       Returns the offset of the current history element.

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b* c\bcu\bur\brr\bre\ben\bnt\bt_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bv_\bo_\bi_\bd)
       Return  the  history  entry  at  the current position, as determined by
       w\bwh\bhe\ber\bre\be_\b_h\bhi\bis\bst\bto\bor\bry\by(\b()\b).  If there is no entry there, return a N\bNU\bUL\bLL\bL pointer.

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b* h\bhi\bis\bst\bto\bor\bry\by_\b_g\bge\bet\bt (_\bi_\bn_\bt _\bo_\bf_\bf_\bs_\be_\bt)
       Return the  history  entry  at  position  _\bo_\bf_\bf_\bs_\be_\bt,  starting  from  h\bhi\bis\bs-\b-
       t\bto\bor\bry\by_\b_b\bba\bas\bse\be.   If  there  is no entry there, or if _\bo_\bf_\bf_\bs_\be_\bt is greater than
       the history length, return a N\bNU\bUL\bLL\bL pointer.

       _\bt_\bi_\bm_\be_\b__\bt h\bhi\bis\bst\bto\bor\bry\by_\b_g\bge\bet\bt_\b_t\bti\bim\bme\be (_\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b*)
       Return the time stamp associated with the history entry passed  as  the
       argument.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_t\bto\bot\bta\bal\bl_\b_b\bby\byt\bte\bes\bs (_\bv_\bo_\bi_\bd)
       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
       history.


   M\bMo\bov\bvi\bin\bng\bg A\bAr\bro\bou\bun\bnd\bd t\bth\bhe\be H\bHi\bis\bst\bto\bor\bry\by L\bLi\bis\bst\bt
       These functions allow the current index into the history list to be set
       or changed.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_s\bse\bet\bt_\b_p\bpo\bos\bs (_\bi_\bn_\bt _\bp_\bo_\bs)
       Set the current history offset to _\bp_\bo_\bs, an absolute index into the list.
       Returns  1  on  success, 0 if _\bp_\bo_\bs is less than zero or greater than the
       number of history entries.

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b* p\bpr\bre\bev\bvi\bio\bou\bus\bs_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bv_\bo_\bi_\bd)
       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 N\bNU\bUL\bLL\bL pointer.

       _\bH_\bI_\bS_\bT_\b__\bE_\bN_\bT_\bR_\bY _\b* n\bne\bex\bxt\bt_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bv_\bo_\bi_\bd)
       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 N\bNU\bUL\bLL\bL pointer.


   S\bSe\bea\bar\brc\bch\bhi\bin\bng\bg t\bth\bhe\be H\bHi\bis\bst\bto\bor\bry\by L\bLi\bis\bst\bt
       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
       _\ba_\bn_\bc_\bh_\bo_\br_\be_\bd,  meaning  that  the string must match at the beginning of the
       history entry.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_s\bse\bea\bar\brc\bch\bh (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg_\b, _\bi_\bn_\bt _\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn)
       Search the history for _\bs_\bt_\br_\bi_\bn_\bg, starting at the current history  offset.
       If  _\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn  is  less  than  0,  then  the search is through previous
       entries, otherwise through subsequent entries.   If  _\bs_\bt_\br_\bi_\bn_\bg  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 _\bs_\bt_\br_\bi_\bn_\bg  was
       found.  Otherwise, nothing is changed, and a -1 is returned.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_s\bse\bea\bar\brc\bch\bh_\b_p\bpr\bre\bef\bfi\bix\bx (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg_\b, _\bi_\bn_\bt _\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn)
       Search  the history for _\bs_\bt_\br_\bi_\bn_\bg, starting at the current history offset.
       The search is anchored: matching lines  must  begin  with  _\bs_\bt_\br_\bi_\bn_\bg.   If
       _\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn  is less than 0, then the search is through previous entries,
       otherwise through subsequent entries.  If _\bs_\bt_\br_\bi_\bn_\bg  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.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_s\bse\bea\bar\brc\bch\bh_\b_p\bpo\bos\bs (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg_\b, _\bi_\bn_\bt _\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn_\b, _\bi_\bn_\bt _\bp_\bo_\bs)
       Search for _\bs_\bt_\br_\bi_\bn_\bg in the history list, starting  at  _\bp_\bo_\bs,  an  absolute
       index  into  the  list.   If _\bd_\bi_\br_\be_\bc_\bt_\bi_\bo_\bn is negative, the search proceeds
       backward from _\bp_\bo_\bs, otherwise forward.  Returns the  absolute  index  of
       the history element where _\bs_\bt_\br_\bi_\bn_\bg was found, or -1 otherwise.


   M\bMa\ban\bna\bag\bgi\bin\bng\bg t\bth\bhe\be H\bHi\bis\bst\bto\bor\bry\by F\bFi\bil\ble\be
       The  History  library can read the history from and write it to a file.
       This section documents the functions for managing a history file.

       _\bi_\bn_\bt r\bre\bea\bad\bd_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be)
       Add the contents of _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be to the history list, a line at a time.  If
       _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  is N\bNU\bUL\bLL\bL, then read from _\b~_\b/_\b._\bh_\bi_\bs_\bt_\bo_\br_\by.  Returns 0 if successful,
       or e\ber\brr\brn\bno\bo if not.

       _\bi_\bn_\bt r\bre\bea\bad\bd_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_r\bra\ban\bng\bge\be (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be_\b, _\bi_\bn_\bt _\bf_\br_\bo_\bm_\b, _\bi_\bn_\bt _\bt_\bo)
       Read a range of lines from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, adding them to the  history  list.
       Start  reading  at  line _\bf_\br_\bo_\bm and end at _\bt_\bo.  If _\bf_\br_\bo_\bm is zero, start at
       the beginning.  If _\bt_\bo is less than _\bf_\br_\bo_\bm, then read until the end of the
       file.   If  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  is N\bNU\bUL\bLL\bL, then read from _\b~_\b/_\b._\bh_\bi_\bs_\bt_\bo_\br_\by.  Returns 0 if
       successful, or e\ber\brr\brn\bno\bo if not.

       _\bi_\bn_\bt w\bwr\bri\bit\bte\be_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be)
       Write the current history to _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, overwriting _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  if  neces-
       sary.   If _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is N\bNU\bUL\bLL\bL, then write the history list to _\b~_\b/_\b._\bh_\bi_\bs_\bt_\bo_\br_\by.
       Returns 0 on success, or e\ber\brr\brn\bno\bo on a read or write error.


       _\bi_\bn_\bt a\bap\bpp\bpe\ben\bnd\bd_\b_h\bhi\bis\bst\bto\bor\bry\by (_\bi_\bn_\bt _\bn_\be_\bl_\be_\bm_\be_\bn_\bt_\bs_\b, _\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be)
       Append the last _\bn_\be_\bl_\be_\bm_\be_\bn_\bt_\bs of the history list to _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be.  If _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
       is  N\bNU\bUL\bLL\bL, then append to _\b~_\b/_\b._\bh_\bi_\bs_\bt_\bo_\br_\by.  Returns 0 on success, or e\ber\brr\brn\bno\bo on
       a read or write error.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_t\btr\bru\bun\bnc\bca\bat\bte\be_\b_f\bfi\bil\ble\be (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be_\b, _\bi_\bn_\bt _\bn_\bl_\bi_\bn_\be_\bs)
       Truncate the history file _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, leaving only the last _\bn_\bl_\bi_\bn_\be_\bs lines.
       If  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  is N\bNU\bUL\bLL\bL, then _\b~_\b/_\b._\bh_\bi_\bs_\bt_\bo_\br_\by is truncated.  Returns 0 on suc-
       cess, or e\ber\brr\brn\bno\bo on failure.


   H\bHi\bis\bst\bto\bor\bry\by E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
       These functions implement history expansion.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_e\bex\bxp\bpa\ban\bnd\bd (_\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg_\b, _\bc_\bh_\ba_\br _\b*_\b*_\bo_\bu_\bt_\bp_\bu_\bt)
       Expand _\bs_\bt_\br_\bi_\bn_\bg, placing the result into _\bo_\bu_\bt_\bp_\bu_\bt, a pointer to  a  string.
       Returns:
              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 :\b:p\bp modifier.
       If an error ocurred in expansion, then _\bo_\bu_\bt_\bp_\bu_\bt  contains  a  descriptive
       error message.

       _\bc_\bh_\ba_\br _\b* g\bge\bet\bt_\b_h\bhi\bis\bst\bto\bor\bry\by_\b_e\bev\bve\ben\bnt\bt (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg_\b, _\bi_\bn_\bt _\b*_\bc_\bi_\bn_\bd_\be_\bx_\b, _\bi_\bn_\bt _\bq_\bc_\bh_\ba_\br)
       Returns  the  text  of the history event beginning at _\bs_\bt_\br_\bi_\bn_\bg + _\b*_\bc_\bi_\bn_\bd_\be_\bx.
       _\b*_\bc_\bi_\bn_\bd_\be_\bx is modified to point to after the event specifier.  At function
       entry,  _\bc_\bi_\bn_\bd_\be_\bx  points to the index into _\bs_\bt_\br_\bi_\bn_\bg where the history event
       specification begins.  _\bq_\bc_\bh_\ba_\br is a character that is allowed to end  the
       event  specification  in addition to the ``normal'' terminating charac-
       ters.

       _\bc_\bh_\ba_\br _\b*_\b* h\bhi\bis\bst\bto\bor\bry\by_\b_t\bto\bok\bke\ben\bni\biz\bze\be (_\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg)
       Return an array of tokens parsed out  of  _\bs_\bt_\br_\bi_\bn_\bg,  much  as  the  shell
       might.    The   tokens   are  split  on  the  characters  in  the  h\bhi\bis\bs-\b-
       t\bto\bor\bry\by_\b_w\bwo\bor\brd\bd_\b_d\bde\bel\bli\bim\bmi\bit\bte\ber\brs\bs  variable,  and  shell  quoting  conventions   are
       obeyed.

       _\bc_\bh_\ba_\br _\b* h\bhi\bis\bst\bto\bor\bry\by_\b_a\bar\brg\bg_\b_e\bex\bxt\btr\bra\bac\bct\bt (_\bi_\bn_\bt _\bf_\bi_\br_\bs_\bt_\b, _\bi_\bn_\bt _\bl_\ba_\bs_\bt_\b, _\bc_\bo_\bn_\bs_\bt _\bc_\bh_\ba_\br _\b*_\bs_\bt_\br_\bi_\bn_\bg)
       Extract a string segment consisting of the _\bf_\bi_\br_\bs_\bt through _\bl_\ba_\bs_\bt arguments
       present in _\bs_\bt_\br_\bi_\bn_\bg.  Arguments are split using h\bhi\bis\bst\bto\bor\bry\by_\b_t\bto\bok\bke\ben\bni\biz\bze\be(\b()\b).


   H\bHi\bis\bst\bto\bor\bry\by V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs
       This section describes the externally-visible variables exported by the
       GNU History Library.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_b\bba\bas\bse\be
       The logical offset of the first entry in the history list.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_l\ble\ben\bng\bgt\bth\bh
       The number of entries currently stored in the history list.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_m\bma\bax\bx_\b_e\ben\bnt\btr\bri\bie\bes\bs
       The maximum number of history entries.  This must be changed using s\bst\bti\bi-\b-
       f\bfl\ble\be_\b_h\bhi\bis\bst\bto\bor\bry\by(\b()\b).

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_w\bwr\bri\bit\bte\be_\b_t\bti\bim\bme\bes\bst\bta\bam\bmp\bps\bs
       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.

       _\bc_\bh_\ba_\br h\bhi\bis\bst\bto\bor\bry\by_\b_e\bex\bxp\bpa\ban\bns\bsi\bio\bon\bn_\b_c\bch\bha\bar\br
       The character that introduces a history event.  The default is !\b!.  Set-
       ting this to 0 inhibits history expansion.

       _\bc_\bh_\ba_\br h\bhi\bis\bst\bto\bor\bry\by_\b_s\bsu\bub\bbs\bst\bt_\b_c\bch\bha\bar\br
       The character that invokes word substitution if found at the start of a
       line.  The default is ^\b^.

       _\bc_\bh_\ba_\br h\bhi\bis\bst\bto\bor\bry\by_\b_c\bco\bom\bmm\bme\ben\bnt\bt_\b_c\bch\bha\bar\br
       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.

       _\bc_\bh_\ba_\br _\b* h\bhi\bis\bst\bto\bor\bry\by_\b_w\bwo\bor\brd\bd_\b_d\bde\bel\bli\bim\bmi\bit\bte\ber\brs\bs
       The  characters  that  separate  tokens  for  h\bhi\bis\bst\bto\bor\bry\by_\b_t\bto\bok\bke\ben\bni\biz\bze\be(\b()\b).   The
       default value is "\b" \\b\t\bt\\b\n\bn(\b()\b)<\b<>\b>;\b;&\b&|\b|"\b".

       _\bc_\bh_\ba_\br _\b* h\bhi\bis\bst\bto\bor\bry\by_\b_n\bno\bo_\b_e\bex\bxp\bpa\ban\bnd\bd_\b_c\bch\bha\bar\brs\bs
       The list of characters which inhibit history expansion if found immedi-
       ately  following  h\bhi\bis\bst\bto\bor\bry\by_\b_e\bex\bxp\bpa\ban\bns\bsi\bio\bon\bn_\b_c\bch\bha\bar\br.   The  default is space, tab,
       newline, \\b\r\br, and =\b=.

       _\bc_\bh_\ba_\br _\b* h\bhi\bis\bst\bto\bor\bry\by_\b_s\bse\bea\bar\brc\bch\bh_\b_d\bde\bel\bli\bim\bmi\bit\bte\ber\br_\b_c\bch\bha\bar\brs\bs
       The list of additional characters which can delimit  a  history  search
       string,  in  addition to space, tab, _\b: and _\b? in the case of a substring
       search.  The default is empty.

       _\bi_\bn_\bt h\bhi\bis\bst\bto\bor\bry\by_\b_q\bqu\buo\bot\bte\bes\bs_\b_i\bin\bnh\bhi\bib\bbi\bit\bt_\b_e\bex\bxp\bpa\ban\bns\bsi\bio\bon\bn
       If non-zero, single-quoted words are not scanned for the history expan-
       sion character.  The default value is 0.

       _\br_\bl_\b__\bl_\bi_\bn_\be_\bb_\bu_\bf_\b__\bf_\bu_\bn_\bc_\b__\bt _\b* h\bhi\bis\bst\bto\bor\bry\by_\b_i\bin\bnh\bhi\bib\bbi\bit\bt_\b_e\bex\bxp\bpa\ban\bns\bsi\bio\bon\bn_\b_f\bfu\bun\bnc\bct\bti\bio\bon\bn
       This  should  be  set to the address of a function that takes two argu-
       ments: a c\bch\bha\bar\br *\b* (_\bs_\bt_\br_\bi_\bn_\bg) and an i\bin\bnt\bt index into  that  string  (_\bi).   It
       should  return  a  non-zero  value if the history expansion starting at
       _\bs_\bt_\br_\bi_\bn_\bg_\b[_\bi_\b] should not be performed; zero  if  the  expansion  should  be
       done.   It  is  intended for use by applications like b\bba\bas\bsh\bh that use the
       history expansion character for additional purposes.  By default,  this
       variable is set to N\bNU\bUL\bLL\bL.

F\bFI\bIL\bLE\bES\bS
       _\b~_\b/_\b._\bh_\bi_\bs_\bt_\bo_\br_\by
              Default filename for reading and writing saved history

S\bSE\bEE\bE A\bAL\bLS\bSO\bO
       _\bT_\bh_\be _\bG_\bn_\bu _\bR_\be_\ba_\bd_\bl_\bi_\bn_\be _\bL_\bi_\bb_\br_\ba_\br_\by, Brian Fox and Chet Ramey
       _\bT_\bh_\be _\bG_\bn_\bu _\bH_\bi_\bs_\bt_\bo_\br_\by _\bL_\bi_\bb_\br_\ba_\br_\by, Brian Fox and Chet Ramey
       _\bb_\ba_\bs_\bh(1)
       _\br_\be_\ba_\bd_\bl_\bi_\bn_\be(3)

A\bAU\bUT\bTH\bHO\bOR\bRS\bS
       Brian Fox, Free Software Foundation
       bfox@gnu.org

       Chet Ramey, Case Western Reserve University
       chet@ins.CWRU.Edu

B\bBU\bUG\bG R\bRE\bEP\bPO\bOR\bRT\bTS\bS
       If  you  find  a bug in the h\bhi\bis\bst\bto\bor\bry\by 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 h\bhi\bis\bst\bto\bor\bry\by library that you have.

       Once  you have determined that a bug actually exists, mail a bug report
       to _\bb_\bu_\bg_\b-_\br_\be_\ba_\bd_\bl_\bi_\bn_\be@_\bg_\bn_\bu_\b._\bo_\br_\bg.  If you have a fix, you are  welcome  to  mail
       that  as  well!   Suggestions  and  `philosophical'  bug reports may be
       mailed to  _\bb_\bu_\bg_\b-_\br_\be_\ba_\bd_\bl_\bi_\bn_\be@_\bg_\bn_\bu_\b._\bo_\br_\bg  or  posted  to  the  Usenet  newsgroup
       g\bgn\bnu\bu.\b.b\bba\bas\bsh\bh.\b.b\bbu\bug\bg.

       Comments and bug reports concerning this manual page should be directed
       to _\bc_\bh_\be_\bt_\b@_\bi_\bn_\bs_\b._\bC_\bW_\bR_\bU_\b._\bE_\bd_\bu.



GNU History 5.0                  2003 July 31                       HISTORY(3)