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KSH(1) KSH(1) NNAAMMEE ksh - Bourne / Korn Shell (Public Domain) SSYYNNOOPPSSIISS kksshh [--sstt] [--cc _c_o_m_m_a_n_d] [_f_i_l_e [_a_r_g_u_m_e_n_t _._._.]] IINNTTRROODDUUCCTTIIOONN This document only summarizes the System V, release 2 shell features. All of the System V features except for ``restricted mode'' are implemented. See also the BUGS section. Features of the Korn shell are described in more detail. Only a subset of the Korn shell features are currently implemented. DDEESSCCRRIIPPTTIIOONN CCoommmmaanndd ssyynnttaaxx The ``#'' character begins a one-line comment, unless the ``#'' occurs inside a word. The tokens ``;'', ``|'', ``&'', ``;;'', ``||'', ``&&'', ``('', and ``)'' stand by themselves. A _w_o_r_d is a sequence of any other non- whitespace characters, which may also contain quoted strings (quote character are ``''', ``"'', ```'', or a matching ``${ }'' or ``$( )'' pair). A _n_a_m_e is an unquoted word made up of letters, digits, or ``_''. Any number of whitespace characters (space and tab) may sepa- rate words and tokens. In the following syntax, { ... }? indicates an optional thing, { ... }* indicates zero or more repetitions, { ... | ... } indicates alternatives. statement: (( list )) {{ list ;; }} ffoorr name { iinn { word }* }? ddoo list ;; ddoonnee { wwhhiillee | uunnttiill } list ;; ddoo list ;; ddoonnee iiff list ;; tthheenn list ;; { eelliiff list ;; tthheenn list ;; }* { eellssee list ;; }?ffii ccaassee name iinn { (( word { || word } )) list ;;;; }* eessaacc ffuunnccttiioonn name {{ list ;; }} name (()) {{ list ;; }} ttiimmee pipe The opening parenthesis of the pattern is optional. Redirection may occur at the beginning or end of a statement. command: { name=word }* { word }* Redirection may occur anywhere in a command. list: cond April 1992 1 KSH(1) KSH(1) cond ;; list cond && list cond: pipe pipe &&&& cond pipe |||| cond pipe: statement { || statement }* AAlliiaass eexxppaannssiioonn Alias expansion occurs when the first word of a statement is a defined alias, except when that alias is already being expanded. It also occurs after the expansion of an alias whose definition ends with a space. SShheellll vvaarriiaabblleess The following standard special variables exist: !!, ##, $$, --, ??. _ In interactive use this parameter is set to the last word of the previous command. When a command is executed this parameter is set to the full path of the command and placed in the environment for the command. See also MMAAIILLPPAATTHH. CDPATH The search path for the _c_d command. ENV If this variable is set at start-up (after any pro- file files are executed), the expanded value is used as shell start-up file. It typically contains function and alias definitions. FCEDIT The editor used by the _f_c command. During startup the shell checks the value of FFCCEEDDIITT, EEDDIITTOORR and finally VVIISSUUAALL to try and determin what command line edit mode to use. Note that this is not strictly ksh compatible behaviour. IFS _I_n_t_e_r_n_a_l _f_i_e_l_d _s_e_p_a_r_a_t_o_r, used during substitution and the _r_e_a_d command. HOME The default directory for the _c_d command. MAIL If set, the user will be informed of the arrival of mail in the named file. This variable is ignored if the MMAAIILLPPAATTHH variable is set. MAILCHECK How often, in seconds, the shell will check for mail in the file(s) specified by MMAAIILL or MMAAIILLPPAATTHH. If 0, the shell checks before each prompt. The default is 600 seconds. April 1992 2 KSH(1) KSH(1) MAILPATH A list of files to be checked for mail. The list is colon separated, and each file may be followed by a ?? and a message to be printed if new mail has arrived. Command and parameter substitution is performed on the message, and the parameter $$__ is set to the name of the file. The default message is ``you have mail in $_''. PATH The search path for executable commands and ..'d files. PPID The process number of the parent of the shell. PS1 PS2 PPSS11 is the primary prompt for interactive shells. Dollar substitution is performed, and !! is replaced with the command number (see _f_c). PWD OLDPWD The current and previous working directories. RANDOM A random integer. The random number generator may be seeded by assigning an integer value to this variable. SECONDS The number of seconds since the shell timer was started or reset. Assigning an integer value to this variable resets the timer. COLUMNS The width to use for the commandline editing (emacs mode only). HISTFILE The name of the file to read initial history from. The default is "$$HHOOMMEE//..ppddkksshh__hhiisstt". When the shell exits it will overwrite this file with its current history. This behaviour will almost certainly cause grief when multiple shells are being run by the same user. Making the file read-only will allow each shell to start with a set history and avoid overwriting the file. HISTSIZE The number of history items to save in HHIISSTTFFIILLEE. SSuubbssttiittuuttiioonn In addition to the System Vr2 substitutions, the following are available. $(command) Like `command`, but no escapes are recognized. April 1992 3 KSH(1) KSH(1) $(<file) Equivalent to $(cat file), but without forking. ${#var} The length of the string value of _v_a_r, or the num- ber of arguments if _v_a_r is ** or @@. ${var#pattern} ${var##pattern} If _p_a_t_t_e_r_n matches the beginning of the value of _v_a_r, the matched text is deleted from the result of substitution. A single ## results in the shortest match, two ##'s results in the longest match. ${var%pattern} ${var%%pattern} Like ## substition, but deleting from the end of the value. EExxpprreessssiioonnss Expressions can be used with the lleett command, as numeric arguments to the tteesstt command, and as the value of an assignment to an integer variable. Expression may contain alpha-numeric variable identifiers and integer constants and may be combined with the follow- ing operators: == != <= < > >= + - * / % ! ( ) CCoommmmaanndd eexxeeccuuttiioonn After evaluation of keyword assignments and arguments, the type of command is determined. A command may execute a shell function, a shell built-in, or an executable file. Any keyword assignments are then performed according to the type of command. In function calls assignments are local to the function. Assignments in built-in commands marked with a persist, otherwise they are temporary. Assignments in executable commands are exported to the sub-process executing the command. Even on systems where the exec() family does not support #! notation for scripts, ksh can be configured to fake it. There are several built-in commands. : Only expansion and assignment are performed. This is the default if a command has no arguments. . _f_i_l_e Execute the commands in _f_i_l_e without forking. The file is searched in the directories of $PATH. Passing arguments is not implemented. April 1992 4 KSH(1) KSH(1) alias [_n_a_m_e==_v_a_l_u_e _._._._] Without arguments, aalliiaass lists all aliases and their values. For any name without a value, its value is listed. Any name with a value defines an alias, see "Alias Expansion" above. Korn's tracked aliases are not implemented, but System V command hashing is (see "hash"). alias -d [_n_a_m_e==_v_a_l_u_e _._._._] Directory aliases for tilde expansion, eg. alias -d fac=/usr/local/usr/facilities cd ~fac/bin break [_l_e_v_e_l_s] builtin _c_o_m_m_a_n_d _a_r_g _._._. _C_o_m_m_a_n_d is executed as a built-in command. cd [_p_a_t_h] Set the working directory to _p_a_t_h. If the parame- ter CDPATH is set, it lists the search path for the directory containing _p_a_t_h. A null path means the current directory. If _p_a_t_h is missing, the home directory ($HOME) is used. If _p_a_t_h is --, the pre- vious working directory is used. If _p_a_t_h is ...., the shell changes directory to the parent direc- tory, as determined from the value of PWD. The PWD and OLDPWD variables are reset. cd _o_l_d _n_e_w The string _n_e_w is substituted for _o_l_d in the cur- rent directory, and the shell attempts to change to the new directory. continue [_l_e_v_e_l_s] echo ... _E_c_h_o is replaced with the alias echo='print' in the Korn shell. eval _c_o_m_m_a_n_d _._._. exec _c_o_m_m_a_n_d _a_r_g _._._. The executable command is executed without forking. If no arguments are given, any IO redirection is permanent. exit [_s_t_a_t_u_s] fc [--ee _e_d_i_t_o_r] [--llnnrr] [_f_i_r_s_t [_l_a_s_t]] _F_i_r_s_t and _l_a_s_t select commands. Commands can be selected by history number, or a string specifing the most recent command starting with that string. The --ll option lists the command on stdout, and --nn April 1992 5 KSH(1) KSH(1) inhibits the default command numbers. The --rr option reverses the order of the list. Without --ll, the selected commands can be edited by the editor specified with the --ee option, or if no --ee is speci- fied, the $$FFCCEEDDIITT editor, then executed by the shell. fc --ee -- [--gg] [_o_l_d==_n_e_w] [_c_o_m_m_a_n_d] Re-execute the selected command (the previous com- mand by default) after performing the optional sub- stitution of _o_l_d with _n_e_w. If --gg is specified, all occurrences of _o_l_d are replaced with _n_e_w. This command is usually accessed with the predefined alias r=``fc -e -''. getopts See the attached manual page. hash [--rr] [_n_a_m_e _._._.] Without arguments, any hashed executable command pathnames are listed. The --rr flag causes all hashed commands to be removed. Each _n_a_m_e is searched as if it were a command name and added to the hash table if it is an executable command. kill [--_s_i_g_n_a_l] _p_r_o_c_e_s_s ... Send a signal (TERM by default) to the named pro- cess. The signal may be specified as a number or a mnemonic from <signal.h> with the SIG prefix removed. let [_e_x_p_r_e_s_s_i_o_n _._._.] Each expression is evaluated, see "Expressions" above. A zero status is returned if the last expression evaluates to a non-zero value, otherwise a non-zero status is returned. Since may expres- sions need to be quoted, _(_( _e_x_p_r _)_) is syntactic sugar for _l_e_t _"_e_x_p_r_". print [--nnrreeuu_n] [_a_r_g_u_m_e_n_t _._._.] PPrriinntt prints its arguments on the standard output, separated by spaces, and terminated with a newline. The --nn option eliminates the newline. By default, certain C escapes are translated. These include \b, \f, \n, \r, \t, \v, and \### (# is an octal digit). \c is equivalent to the --nn option. This expansion may be inhibitted with the --rr option, and may be re-enabled with the addition of the --ee option. read [--rruu_n] _n_a_m_e _._._. The first variable name may be of the form _n_a_m_e??_p_r_o_m_p_t. April 1992 6 KSH(1) KSH(1) readonly [_n_a_m_e _._._.] return [_s_t_a_t_u_s] set [++--_[_a_-_z_]] [++--oo _k_e_y_w_o_r_d] ... Set (--) or clear (++) a shell option: -a allexport all new variable are created with export attribute -e errexit exit on non-zero sta- tus [incorrect] bgnice background jobs are run with lower priority emacs BRL emacs-like line editing ignoreeof shell will not exit of EOF, must use _e_x_i_t -k keyword variable assignments are recognized anywhere in command markdirs [not implemented] -m monitor job control enabled (default for interactive shell) -n noexec compile input but do not execute (ignored if interactive) -f noglob don't expand file- names -u nounset dollar expansion of unset variables is an error -v verbose echo shell commands on stdout when compiling -h trackall add command pathnames to hash table vi VI-like line editing -x xtrace echo simple commands while executing set [----] _a_r_g _._._. Set shell arguments. shift [_n_u_m_b_e_r] test See the attached manual page. times trap [_h_a_n_d_l_e_r] [_s_i_g_n_a_l _._._.] typeset [++--iirrttxx] [_n_a_m_e[==_v_a_l_u_e] ...] If no arguments are given, lists all variables and their attributes. If options but no names are given, lists variables with specified attributes, and their values if unless ``+'' is used. April 1992 7 KSH(1) KSH(1) If names are given, set the attributes of the named vari- ables. Variables may also be assigned a value. If used inside a function, the created variable are local to the function. The attributes are as follows. -iThe variable's value is stored as an integer. -xThe variable is exported to the enviroment. -rThe variable is read-only cannot be reassigned a value. -tTrace (not implemented). -fList functions instead of variable. uulliimmiitt [ --<<OOZZ>> ] [ _n ] --cc Impose a size limit of _n blocks on the size of core dumps. --dd Impose a size limit of _n blocks on the size of the data area. --ff Impose a size limit of _n blocks on files writ- ten by the shell and its child processes (files of any size may be read). --mm Impose a soft limit of _n blocks on the size of physical memory. --tt Impose a time limit of _n seconds to be used by each process. If no option is given, --ff is assumed. If _n is omitted, the current limit is printed. As far as uulliimmiitt is concerned, a ``block'' is 512 bytes. You may lower your own resource limit, but only a super-user (see _s_u(1M)) can raise a limit. umask [_v_a_l_u_e] unalias _n_a_m_e _._._. The aliases for the given names are removed. unset [--ff] _n_a_m_e _._._. wait [_p_r_o_c_e_s_s_-_i_d] whence [--vv] name ... For each name, the type of command is listed. The --vv flag causes function and alias values to be listed. JJoobb CCoonnttrrooll Job control features are enabled by the --mm or --oo mmoonniittoorr flags. When job control is enabled, and the system April 1992 8 KSH(1) KSH(1) supports job control, background commands and foreground commands that have been stopped (usually by a SIGTSTP sig- nal generated by typing _^_Z) are placed into separate indi- vidual _p_r_o_c_e_s_s _g_r_o_u_p_s. The following commands are used to manipulate these process groups: jjoobbss Display information about the controlled jobs. The job number is given preceeded by a percent sign, followed by a plus sign if it is the ``current job'', or by a minus sign if it is the ``previous job'', then the process group number for the job, then the command. kkiillll [--_s_i_g_n_a_l] _j_o_b ... Send a signal (TERM by default) to the named job process group. ffgg [ _j_o_b ] Resume the stopped foreground job in the foreground. If the process group _n is not specified then the ``current job'' is resumed. bbgg [ _j_o_b ] Resume the stopped foreground job in the background. If the process group _n is not specified then the ``current job'' is resumed. The ffgg, bbgg, kkiillll, and wwaaiitt commands may refer to jobs with the following ``percent'' sequences. The percent sign is optional with the fg and bg commands. %%++(%%--) If there is a ``current job'' (``previous job''), then that job is selected. %%_n If the specified job number is one of the known jobs, then that job is selected. %%_s_t_r_i_n_g If the string matches the initial part of a job's command, then that job is selected. %%??_s_t_r_i_n_g As above, but the string may match any portion of the command. If the system does not support job control, monitor mode enables job reporting. The jobs and kill commands func- tions as above, and you will be informed when background jobs complete. Fg and bg are not availiable. IInntteerraaccttiivvee IInnppuutt LLiinnee EEddiittiinngg When the eemmaaccss option is set, interactive input line edit- ing is enabled. This mode is slightly different from the emacs mode in AT&T's KornShell. In this mode various _e_d_i_t_i_n_g _c_o_m_m_a_n_d_s (typically bound to one or more control characters) cause immediate actions without waiting for a new-line. Several _e_d_i_t_i_n_g _c_o_m_m_a_n_d_s are bound to particu- lar control characters when the shell is invoked; these bindings can be changed using the following commands: bbiinndd The current bindings are listed. April 1992 9 KSH(1) KSH(1) bbiinndd [ _s_t_r_i_n_g ] = [ _e_d_i_t_i_n_g_-_c_o_m_m_a_n_d ] The specified _e_d_i_t_i_n_g _c_o_m_m_a_n_d is bound to the given _s_t_r_i_n_g, which should con- sist of a control character (which may be written using ``caret notation'' ^^_x), optionally preceded by one of the two prefix characters. Future input of the _s_t_r_i_n_g will cause the _e_d_i_t_i_n_g _c_o_m_m_a_n_d to be immediately invoked. Note that although only two prefix characters (normal ESC and ^X) are supported, some multi-character sequences can be supported: bind '^[['=prefix-2 bind '^XA'=up-history bind '^XB'=down-history bind '^XC'=forward-char bind '^XC'=backward-char will bind the arrow keys on an ANSI terminal. Of course some escape sequences won't work out quite that nicely. bbiinndd --mm [ _s_t_r_i_n_g ] = [ _s_u_b_s_t_i_t_u_t_e ] The specified input _s_t_r_i_n_g will after- wards be immediately replaced by the given _s_u_b_s_t_i_t_u_t_e string, which may contain _e_d_i_t_i_n_g _c_o_m_m_a_n_d_s. The following _e_d_i_t_i_n_g _c_o_m_m_a_n_d_s are available; first the command name is given followed by its default binding (if any) using caret notation (note that the ASCII ESC charac- ter is written as ^[), then the editing function performed is decribed. Note that _e_d_i_t_i_n_g _c_o_m_m_a_n_d names are used only with the bbiinndd command. Furthermore, many _e_d_i_t_i_n_g _c_o_m_m_a_n_d_s are useful only on terminals with a visible cur- sor. The default bindings were chosen to resemble corre- sponding EMACS key bindings. The users tty characters (eg. erase) are bound to reasonable substitutes. aabboorrtt ^^GG Useful as a response to a request for a sseeaarrcchh-- hhiissttoorryy pattern in order to abort the search. aauuttoo--iinnsseerrtt Simply causes the charac- ter to appear as literal input. (Most ordinary characters are bound to this.) bbaacckkwwaarrdd--cchhaarr ^^BB Moves the cursor backward one character. bbaacckkwwaarrdd--wwoorrdd ^^[[bb Moves the cursor backward to the beginning of a word. bbeeggiinnnniinngg--ooff--lliinnee ^^AA Moves the cursor to the April 1992 10 KSH(1) KSH(1) beginning of the input line (after the prompt string). ccoommpplleettee ^^[[^^[[ Automatically completes as much as is unique of the hashed command name or the file name containing the cursor. If the entire remaining command or file name is unique a space is printed after its comple- tion, unless it is a directory name in which case // is postpended. If there is no hashed command or file name with the cur- rent partial word as its prefix, a bell character is output (usually causing a ``beep''). ccoommpplleettee--ccoommmmaanndd ^^XX^^[[ Automatically completes as much as is unique of the hashed command name having the partial word up to the cursor as its prefix, as in the ccoommpplleettee command described above. Only command and function names seen since the last hhaasshh --rr command are available for completion; the hhaasshh command may be used to register additional names. ccoommpplleettee--ffiillee ^^[[^^XX Automatically completes as much as is unique of the file name having the par- tial word up to the cursor as its prefix, as in the ccoommpplleettee command described above. ccooppyy--llaasstt--aarrgg ^^[[__ The last word of the pre- vious command is inserted at the cursor. Note I/O redirections do not count as words of the command. ddeelleettee--cchhaarr--bbaacckkwwaarrdd EERRAASSEE Deletes the character before the cursor. ddeelleettee--cchhaarr--ffoorrwwaarrdd Deletes the character after the cursor. ddeelleettee--wwoorrdd--bbaacckkwwaarrdd ^^[[EERRAASSEE Deletes characters before the cursor back to the beginning of a word. ddeelleettee--wwoorrdd--ffoorrwwaarrdd ^^[[dd Deletes characters after the cursor up to the end April 1992 11 KSH(1) KSH(1) of a word. ddoowwnn--hhiissttoorryy ^^NN Scrolls the history buffer forward one line (later). Each input line originally starts just after the last entry in the history buffer, so ddoowwnn--hhiissttoorryy is not useful until either sseeaarrcchh--hhiissttoorryy or uupp-- hhiissttoorryy has been per- formed. eenndd--ooff--lliinnee ^^EE Moves the cursor to the end of the input line. eeoott ^^__ Acts as an end-of-file; this is useful because edit-mode input disables normal terminal input canonicalization. eeoott--oorr--ddeelleettee ^^DD Acts as eot if alone on a line; otherwise acts as delete-char-forward. eexxcchhaannggee--ppooiinntt--aanndd--mmaarrkk ^^XX^^XX Places the cursor where the mark is, and sets the mark to where the cursor was. ffoorrwwaarrdd--cchhaarr ^^FF Moves the cursor forward one position. ffoorrwwaarrdd--wwoorrdd ^^[[ff Moves the cursor forward to the end of a word. kkiillll--lliinnee KKIILLLL Deletes the entire input line. kkiillll--ttoo--eeooll ^^KK Deletes the input from the cursor to the end of the line. kkiillll--rreeggiioonn ^^WW Deletes the input between the cursor and the mark. lliisstt ^^[[?? Prints a sorted, colum- nated list of hashed com- mand names or file names (if any) that can complete the partial word contain- ing the cursor. Directory names have // postpended to them, and executable file names are followed by **. lliisstt--ccoommmmaanndd ^^XX?? Prints a sorted, colum- nated list of hashed com- mand names (if any) that can complete the partial word containing the cur- sor. lliisstt--ffiillee Prints a sorted, colum- nated list of file names (if any) that can complete April 1992 12 KSH(1) KSH(1) the partial word contain- ing the cursor. File type indicators are postpended as described under lliisstt above. nneewwlliinnee ^^JJ _a_n_d ^^MM Causes the current input line to be processed by the shell. (The current cursor position may be anywhere on the line.) nneewwlliinnee--aanndd--nneexxtt ^^OO Causes the current input line to be processed by the shell, and the next line from history becomes the current line. This is only useful after an up- history or search-history. nnoo--oopp QQUUIITT Does nothing. pprreeffiixx--11 ^^[[ Introduces a 2-character command sequence. pprreeffiixx--22 ^^XX Introduces a 2-character command sequence. qquuoottee ^^^^ The following character is taken literally rather than as an _e_d_i_t_i_n_g _c_o_m_- _m_a_n_d. rreeddrraaww ^^LL Reprints the prompt string and the current input line. sseeaarrcchh--cchhaarraacctteerr ^^]] Search forward in the cur- rent line for the next keyboard character. sseeaarrcchh--hhiissttoorryy ^^RR Enter incremental search mode. The internal his- tory list is searched backwards for commands matching the input. An initial ``^'' in the search string anchors the search. The escape key will leave search mode. Other commands will be executed after leaving search mode (unless of course they are prefixed by escape, in which case they will almost certainly do the wrong thing). Suc- cessive sseeaarrcchh--hhiissttoorryy commands continue search- ing backward to the next previous occurrence of the pattern. The history buffer retains only a April 1992 13 KSH(1) KSH(1) finite number of lines; the oldest are discarded as necessary. sseett--mmaarrkk--ccoommmmaanndd ^^]]<<ssppaaccee>> Search forward in the cur- rent line for the next keyboard character. ssttuuffff On systems supporting it, pushes the bound character back onto the terminal input where it may receive special processing by the terminal handler. ssttuuffff--rreesseett Acts like ssttuuffff, then aborts input the same as an interrupt. ttrraannssppoossee--cchhaarrss ^^TT Exchanges the two charac- ters on either side of the cursor, or the two previ- ous characters if the cur- sor is at end of line. uupp--hhiissttoorryy ^^PP Scrolls the history buffer backward one line (ear- lier). yyaannkk ^^YY Inserts the most recently killed text string at the current cursor position. yyaannkk--ppoopp ^^[[yy Immediately after a yyaannkk, replaces the inserted text string with the next pre- vious killed text string. FFIILLEESS ~/.profile /etc/profile SSEEEE AALLSSOO Sh(1) on System V or Sun OS. _U_N_I_X _S_h_e_l_l _P_r_o_g_r_a_m_m_i_n_g_, Stephan G. Kochan, Patrick H. Wood, Hayden. _K_o_r_n_S_h_e_l_l_: _C_o_m_m_a_n_d _a_n_d _P_r_o_g_r_a_m_m_i_n_g _L_a_n_g_u_a_g_e _(_n_o_t _y_e_t _p_u_b_- _l_i_s_h_e_d_)_, Morris Bolsky and David Korn. AAUUTTHHOORRSS Based on the public domain 7th edition Bourne shell. System V and Korn modifications by Eric Gisin, with con- tributions by Ron Natalie, Arnold Robbins, Doug Gwyn, Erik Baalbergen, AT&T (getopt(3)), John McMillan and Simon Ger- raty. April 1992 14 KSH(1) KSH(1) DDIIFFFFEERREENNCCEESS FFRROOMM AATT&&TT VVEERRSSIIOONN The sseelleecctt statement is not implemented. Variable arrays are not implemented. Variable attributes other than inte- ger are not implemented. The EERRRR and EEXXIITT traps are not implemented for functions. Alias expansion is inhibited at the beginning of an alias definition in the AT&T ver- sion. Korn evaluates expressions differently [elaborate]. BBUUGGSS Interactive shells may occasionally hang while waiting for a job in the BSD version. The 8th bit is stripped in emacs mode. Quoting double-quote (") characters inside back-quote (`) inside double-quotes does not behave properly. Why are you doing this? The emacs mode can ``lose'' stty command done by the user. Unsetting special variables may cause unexpected results. Functions declared as having local scope really have global scope. Here documents inside functions do not work correctly. Exit on error (sseett --ee or sseett --oo eerrrreexxiitt) does not work correctly. April 1992 15 TEST(1) TEST(1) NNAAMMEE test - test condition (Korn and 8th edition) SSYYNNOOPPSSIISS tteesstt _e_x_p_r_e_s_s_i_o_n [[ _e_x_p_r_e_s_s_i_o_n ]] DDEESSCCRRIIPPTTIIOONN TTeesstteevvaalluuttaatteess tthhee _e_x_p_r_e_s_s_i_o_n aanndd rreettuurrnnss zzeerroo ssttaattuuss iiff ttrruuee,, aanndd nnoonn--zzeerroo ssttaattuuss ootthheerrwwiissee.. IItt iiss nnoorrmmaallllyy uusseedd aass tthhee ccoonnttrroolllliinngg ccoommmmaanndd ooff tthhee iiff aanndd wwhhiillee ssttaatteemmeennttss.. The following basic expressions are available. -r file file exists and is readable -w file file exists and is writable -x file file exists and is executable -f file file is a regular file -d file file is a directory -c file file is a character special device -b file file is a block spe- cial device -p file file is a named pipe -u file file mode has setuid bit -g file file mode has setgid bit -k file file mode has sticky bit -s file file is not empty -L file file is a symbolic link -S file file is a socket file -nt file first file is newer than second file file -ot file first file is older than second file file -ef file first file is the same file as second file -t filedes file descriptor is a tty device string string is not null -z string string is null -n string string is not null string = string strings are equal string != string strings are not equal number -eq number numbers compare equal Korn shell January 1988 1 TEST(1) TEST(1) number -ne number numbers compare not equal number -ge number numbers compare greater than or equal number -gt number numbers compare greater than number -le number numbers compare less than or equal number -lt number numbers compare less than The above basic expressions may be combined with the fol- lowing operators. expr -o expr logical or expr -a expr logical and ! expr logical not ( expr ) grouping AAUUTTHHOORR Erik Baalbergen. Modified by Arnold Robbins. Korn shell January 1988 2 GETOPTS(1) GETOPTS(1) NNAAMMEE getopts - parse command options SSYYNNOOPPSSIISS ggeettooppttss optstring name [arg ...] DDEESSCCRRIIPPTTIIOONN _g_e_t_o_p_t_s is used by shell procedures to parse positional parameters and to check for legal options. It supports all applicable rules of the command syntax standard (see Rules 3-10, _i_n_t_r_o(1)). It should be used in place of the _g_e_t_o_p_t(1) command. (See the WWAARRNNIINNGG, below.) _o_p_t_s_t_r_i_n_g must contain the option letters the command using _g_e_t_o_p_t_s will recognize; if a letter is followed by a colon, the option is expected to have an argument which should be separated from it by white space. Each time it is invoked, _g_e_t_o_p_t_s will place the next option in the shell variable _n_a_m_e and the index of the next argument to be processed in the shell variable OOPPTTIINNDD. Whenever the shell or a shell procedure is invoked, OOPPTTIINNDD is initialized to 11. When an option requires an option-argument, _g_e_t_o_p_t_s places it in the shell variable OOPPTTAARRGG. If an illegal option is encountered, ?? will be placed in _n_a_m_e. When the end of the options is encountered, _g_e_t_o_p_t_s exits with a non-zero exit status. The special option ``----'' may be used to delimit the end of the options. By default, _g_e_t_o_p_t_s parses the positional parameters. If extra arguments (_a_r_g ...) are given on the _g_e_t_o_p_t_s command line, _g_e_t_o_p_t_s will parse them instead. So all new commands will adhere to the command syntax standard described in _i_n_t_r_o(1), they should use _g_e_t_o_p_t_s(1) or _g_e_t_o_p_t(3C) to parse positional parameters and check for options that are legal for that command (see WWAARRNNIINNGGSS, below). EEXXAAMMPPLLEE The following fragment of a shell program shows how one might process the arguments for a command that can take the options aa or bb, as well as the option oo, which requires an option-argument: wwhhiillee ggeettooppttss aabboo:: cc ddoo ccaassee $$cc iinn aa||bb)) FFLLAAGGSS==$$FFLLAAGGSS$$cc;;;; Korn shell January 1988 1 GETOPTS(1) GETOPTS(1) oo)) OOAARRGG==$$OOPPTTAARRGG;;;; \\??)) eecchhoo $$UUSSAAGGEE 11>>&&22 eexxiitt 22;;;; eessaacc ddoonnee sshhiifftt OOPPTTIINNDD--11 This code will accept any of the following as equivalent: ccmmdd --aa --bb --oo ""xxxxxx zz yyyy"" ffiillee ccmmdd --aa --bb --oo ""xxxxxx zz yyyy"" ---- ffiillee ccmmdd --aabb --oo ""xxxxxx zz yyyy"" ffiillee ccmmdd --aabb --oo ""xxxxxx zz yyyy"" ---- ffiillee SSEEEE AALLSSOO intro(1), sh(1). getopt(3C) in the _P_r_o_g_r_a_m_m_e_r_'_s _R_e_f_e_r_e_n_c_e _M_a_n_u_a_l. _U_N_I_X _S_y_s_t_e_m _V _R_e_l_e_a_s_e _3_._0 _R_e_l_e_a_s_e _N_o_t_e_s. WWAARRNNIINNGG Although the following command syntax rule (see _i_n_t_r_o(1)) relaxations are permitted under the current implementa- tion, they should not be used because they may not be sup- ported in future releases of the system. As in the EEXXAAMM-- PPLLEE section above, aa and bb are options, and the option oo requires an option-argument: ccmmdd --aabbooxxxxxx ffiillee (Rule 5 violation: options with option-arguments must not be grouped with other options) ccmmdd --aabb --ooxxxxxx ffiillee (Rule 6 violation: there must be white space after an option that takes an option-argument) Changing the value of the shell variable OOPPTTIINNDD or parsing different sets of arguments may lead to unexpected results. DDIIAAGGNNOOSSTTIICCSS _g_e_t_o_p_t_s prints an error message on the standard error out- put when it encounters an option letter not included in _o_p_t_s_t_r_i_n_g. Korn shell January 1988 2