LINE(1) USER COMMANDS LINE(1) NAME line - a shell with features reminiscent of csh SYNOPSIS line [-a ] [-c ] [-d ] [-f ] [-p ] [-s ] [-t ] line -h[elp] DESCRIPTION ›3mline ›0mis a command interpreter meant to augment the regular CLI environment with aliasing, history, file completion, and some built-in commands. The result is a quite useable subset of ›3mcsh ›0mfeatures, in under 20k. OPTIONS Parameters may be given to ›3mline ›0mfrom the command line and/or the environment variable LINEOPTS (see ENVIRONMENT, below). Values given for a parameter on the command line supercede any for that parameter in LINEOPTS. All options which require additional arguments will first look at the text immediately following the option, and if the needed parameter is not found, will take the next argument. Upshot: as an example, both "-ablarg" and "-a blarg" are valid syntax. -a ›3mmaxaliases ›0mThe maximum number of aliases that can exist during the session. Space for aliases is allocated dynamically. Defaults to 20. -c ›3mhistsize ›0mDefines the size of the history cache. A full line-length buffer is allocated for each of these. Default is 20. -d ›3mdirstack ›0mThe depth of the directory stack used by push, pop, and dirs. One longword is used per entry. Default is 5. -f ›3mignorelist ›0mGives filename suffixes to ignore when doing filename completion. A list of suffixes can be given by separating the suffixes by vertical bars (note no whitespace is allowed around the vertical bar). The default is ""; a more useful one is ".o|~|.info". -h[elp] Prints short synopsis of command line options. -p ›3mprompt ›0mSets the user prompt for the session. The default is "%N> ". The various per cent codes that have special meaning for the prompt are described in PROMPT, below. -1- LINE(1) USER COMMANDS LINE(1) -s ›3mstartup ›0mThe startup file ›3mline ›0mlooks for commands in. It defaults to "s:.linerc". This file can contain any command that you would normally enter at the user prompt, and comments may be added by putting a hash mark ("#") as the first non-whitespace character of a line. -t ›3mtmpdir ›0mThe directory temporary files (such as those used to implement pipes) are stored in. Defaults to "tmp:". It is sufficient to assign tmp: instead, usually to ram:. USAGE Aliasing A list of aliases is maintained that can be created, modified, or destroyed with the "alias" and "unalias" builtins. Aliases associate a string with a word. Whenever that word is the first one in a command, the string is substituted for it, and the line is re-evaluated. There are some special character combinations that can occur in the strings: "!'" will be replaced by a quotation mark (handy, since many times alias strings will need to be quoted themselves), and "!*", which puts any arguments following the alias in at that particular spot, instead of appending them. Multiple "!'" and "!*" are allowed. Aliases may include other aliases within their definitions, but cycles or loops are not permitted. Command Line Parsing Input lines are first broken up into commands at pipe symbols ("|") and command seperators (";"). Note that "|" and ";" must be surrounded by space(s); this restriction imposed largely because the vertical bar is a valid character in AmigaDOS wildcards. The resulting line then has I/O redirection removed ("< file" and "> file" -- space is optional between the redirection symbol and the filename), and inconsistencies are checked for. For example, both output redirection and a pipe to the next command are illegal. Null commands are not allowed. Then, history substitution is performed on the first word in each command. For each substitution, the entire line is re-evaluated from the beginning. Alias expansion is then attempted on the first word in each command. Every successful expansion will also cause the line to be re-evaluated, WITHOUT HISTORY SUBSTITUTION. Lastly, each command is checked to see if it is a built-in function, and if so, it is executed. Note built-in commands like "cls" may be over-ridden by capitalizing all or part of the word: "Cls" is not a built-in command. Finally, the commands are executed using ARP's SyncRun(). Editing Keys ^I Filename completion. -2- LINE(1) USER COMMANDS LINE(1) ^J Accept input line. ^M Same as ^J. ^Q Quits from line. See also the "exit" builtin. ^U Erases the current input line. ^X Same as ^U. ^W Erases the previous word. Filename Completion Pressing ^I will engage filename completion. ›3mline ›0mwill attempt to match a partially typed (or even non-existent) filename with one in the directory. The case of a match will be changed to reflect that of the actual filename. If an unambiguous match cannot be made, the longest possible unambiguous part will be returned. Filenames with certain suffixes can be ignored; see the description of the "-f" command line argument for details. History Substitution A history of commands is maintained by ›3mline ›0mup to a limit set by the "-c" command line argument (default 20). The history mechanism allows these to be referenced on the current command line. The first word of every command is examined, and if it is one of several forms, the appropriate substitution is made, any arguments following the history reference are appended to the new command, and the line is re-evaluated. The history forms are: !! Refers to the previous command. Any text in the word following this is appended to the substituted command. !n Refers to command number ›3mn. ›0mAny text following the number is appended to the substituted command. !-n Refers to the current command line minus ›3mn. ›0mAs before, text following the number is appended. "!-1" and "!!" are equivalent forms. !str Refers to the last command line containing ›3mstr. ›0m^m^n Refers to the last command line, but with all occurances of ›3mm ›0mreplaced with ›3mn. n ›0mmay be the null string, in which case all occurances of ›3mm ›0mare deleted. Optionally, this form may be followed by a carat. The carat is ignored, but any text in the word following the carat is appended to the substituted command. The "history" builtin may be used to display the current contents of the history cache. I/O Redirection ›3mline ›0msupports the redirection of standard input and standard output, as well as a command pipeline facility. -3- LINE(1) USER COMMANDS LINE(1) < ›3mfile ›0mTake input for the command from ›3mfile. ›0mThe space is optional after the "<". Input re-direction may occur at any position after the first word of a command. > ›3mfile ›0mRedirect the standard output of the command to ›3mfile. ›0mIf the file does not exist, it is created; if it exists, its former contents are overwritten. As for input redirection, the space between the ">" and the filename is optional, and it may be placed at any place except for the first word of a command. BUILT-IN COMMANDS alias alias alias The first form prints a list of all the aliases currently known to the shell. The second prints out the definition of a particular alias. The last creates a new alias or changes the definition of an old one. See USAGE for details on aliases. cls Clears the screen. dirs Prints the contents of the directory stack. The first name printed is at the top of the stack. exit Exits from ›3mline. ›0mhistory Prints the contents of the history cache. pop Makes the top entry in the directory stack the current working directory. push Pushes the current working directory onto the directory stack. unalias [ ...] Removes aliases from the alias list. ver Prints the version number and author of ›3mline. ›0mUse it now. Use it often. PROMPT In addition to regular characters, the prompt may contain any of the following special codes: %b The basename of the current working directory. %c The current command number. -4- LINE(1) USER COMMANDS LINE(1) %e The ASCII escape character. %h The ASCII backspace character. %i The ASCII tab character. %n The ASCII newline character. %p The full pathname of the current working directory. %N The CLI number. Any unrecognised escapes (including "%%") expand to the escaped character. ENVIRONMENT As opposed to typing them at the command line, arguments to ›3mline ›0mmay be placed in the environment variable LINEOPTS (ARP's GetEnv() routine is used to get the variable; while it recognises Manx-style environment variables, it is recommended that Commodore's ENV: be used for future compatibility). LINEOPTS is filtered through ARP's GADS as well, so any features inherent to it can be used. A problem arises regarding how to place the quote character into an environment variable. It can be put there by escaping it with an asterisk ("*"). For example, my ›3mStartup-Sequence ›0mincludes the line: setenv LINEOPTS "-p *"%c %b >*" -f *".o|~|.info*"" AUTHOR John Aycock, 1990. See copyright notice for restrictions. FILES/DEVICES s:.linerc Default startup file. tmp: Directory for temporary files. BUGS Shell scripts should be executed somehow. Running ›3mExecute ›0mdoesn't seem to work at all. The number of arguments in an environment variable is limited to 20. Crash and burn will occur in history substitution and alias expansion near the ends of long lines (256 bytes). If your lines are this long, you probably deserve to crash. Pathnames (as printed by the %p prompt option or dirs) cannot be longer than 256 bytes, or a visit from the GURU will result. -5-