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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  History  library  is able to keep track of those
       lines, associate arbitrary data with each line,  and  uti-
       lize  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 identical 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  cur-
       rent  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 second 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_\b-
       _\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 several words that would oth-
       erwise be separated are  considered  one  word  when  sur-
       rounded  by  quotes  (see  the description of h\bhi\bis\bst\bto\bor\bry\by_\b_t\bto\bok\bk-\b-
       e\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 history 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'.




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HISTORY(3)                                             HISTORY(3)


       !\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 trailing ?\b? may be omitted if _\bs_\bt_\br_\bi_\bn_\bg is followed
              immediately by a newline.
       ^\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\bdi\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 separated by single spaces.

       0\b0 (\b(z\bze\ber\bro\bo)\b)
              The  zeroth  word.  For the shell, this is the com-
              mand 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 specifi-
       cation, 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.



GNU History 4.3          2002 January 31                        2





HISTORY(3)                                             HISTORY(3)


       q\bq      Quote the substituted words, escaping further  sub-
              stitutions.
       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  back-
              slash.  If & appears in _\bn_\be_\bw, it is replaced by _\bo_\bl_\bd.
              A single 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 substitutions 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.

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 programs.

   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, associ-
       ating  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  available  which provides for a consistent user inter-
       face across different programs.

       The user using programs written with the  History  library
       has  the benefit of a consistent user interface with a set
       of well-known commands for manipulating the text of previ-
       ous  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 advantage of command line edit-
       ing.

       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 sup-
       plies extern declarations for all of the library's  public



GNU History 4.3          2002 January 31                        3





HISTORY(3)                                             HISTORY(3)


       functions  and  variables,  and declares all of the public
       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  his-
       tory 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;
         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 structure:

       /*
        * 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 vari-
       ous 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)



GNU History 4.3          2002 January 31                        4





HISTORY(3)                                             HISTORY(3)


       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 associ-
       ated data field (if any) is set to N\bNU\bUL\bLL\bL.

       _\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_\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_\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 you can dispose of the 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\bi-\b-
       f\bfl\ble\be_\b_h\bhi\bis\bst\bto\bor\bry\by(\b()\b)).   history was stifled.  The value is posi-
       tive 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 his-
       tory 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)



GNU History 4.3          2002 January 31                        5





HISTORY(3)                                             HISTORY(3)


       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\bst\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.

       _\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 his-
       tory 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 containing a specific string.   Searching  may  be
       performed  both forward and backward from the current his-
       tory 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 sub-
       sequent  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



GNU History 4.3          2002 January 31                        6





HISTORY(3)                                             HISTORY(3)


       _\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 man-
       aging 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_\b-
       _\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_\b-
       _\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_\b-
       _\bn_\ba_\bm_\be  if  necessary.   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



GNU History 4.3          2002 January 31                        7





HISTORY(3)                                             HISTORY(3)


       truncated.  Returns 0 on success, 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 executed, 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''  termi-
       nating characters.

       _\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\bst\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.




GNU History 4.3          2002 January 31                        8





HISTORY(3)                                             HISTORY(3)


       _\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\bif\bfl\ble\be_\b_h\bhi\bis\bst\bto\bor\bry\by(\b()\b).

       _\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!.  Setting this to 0 inhibits  history  expan-
       sion.

       _\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  his-
       tory  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\bk-\b-
       e\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 immediately 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 his-
       tory 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 expansion 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  arguments:  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 per-
       formed; 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 his-
              tory





GNU History 4.3          2002 January 31                        9





HISTORY(3)                                             HISTORY(3)


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_\b-
       _\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 4.3          2002 January 31                       10