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diff --git a/static/v10/man1/newcsh.1 b/static/v10/man1/newcsh.1 new file mode 100644 index 00000000..56f29c23 --- /dev/null +++ b/static/v10/man1/newcsh.1 @@ -0,0 +1,366 @@ +.TH NEWCSH 1 +.UC 4 +.bd S 3 +.SH NAME +newcsh \- description of new csh features (over oldcsh) +.SH SYNOPSIS +.B csh +\fIcsh-options\fR +.SH SUMMARY +This is a summary of features new in +.IR csh (1) +in this version of the system; an older version of +.I csh +is available as +.I oldcsh. +This newer +.I csh +has some new process control primitives and a few other new features. +Users of +.I csh +must (and automatically) use the new terminal driver (summarized in +.IR newtty(4) +and completely described with the old in +.IR tty (4)) +which allows generation of some new +interrupt signals from the keyboard which tell jobs to stop, +and arbitrates access to the terminal; +on CRT's the command ``stty crt'' is +normally placed in the +.I .login +file to be executed at login, +to set other useful modes of this terminal driver. +.PP +.B "Jobs." +.PP +The most important new feature in this shell is the control of +.I jobs. +A job is associated with each pipeline, where a pipeline is either +a simple command like ``date'', or a pipeline like ``who | wc''. +The shell keeps a table of current jobs, and assigns them small +integer numbers. +When you start a job in the background, the shell prints a line +which looks like: +.PP +\ \ \ \ [1] 1234 +.PP +this indicating that the job which was started asynchronously with ``&'' +is job number 1 and has one (top-level) process, whose process id is 1234. +The set of current jobs is listed by the +.I jobs +command. +.PP +If you are running a job and wish to do something else you may hit the +key ^Z (control-Z) which sends a +.I stop +signal to the current job. The shell will then normally indicate that +the job has been ``Stopped'', and print another prompt. +You can then +put the job in the background with the command ``bg'', or run +some other commands and then return the job to the foreground with +``fg''. +A ^Z takes effect immediately and is like an interrupt in that +pending output and unread input are discarded when it is typed. +There is another special key ^Y which does not generate a stop signal +until a program attempts to +.IR read (2) +it. +This can usefully be typed ahead when you have prepared some commands +for a job which you wish to stop after it has read them. +.PP +A job being run in the background will stop if it tries to read +from the terminal. Background jobs are normally allowed to produce output, +but this can be disabled by doing ``stty tostop''. If you set this +tty option, then background jobs will stop when they try to produce +output like they do when they try to read input. +.PP +There are several ways to refer to jobs in the shell. The character +``%'' introduces a job name. If you wish to refer to job number 1, you can +name it as ``%1''. Just naming a job brings it to the foreground; thus +``%1'' is a synonym for ``fg %1'', bringing job 1 back into the foreground. +Similarly saying ``%1 &'' resumes job 1 in the background. +Jobs can also be named by prefixes of the string typed in to start them, +if these prefixes are unambiguous, thus ``%ex'' would normally restart +a suspended +.IR ex (1) +job, if there were only one suspended job whose name began with +the string ``ex''. It is also possible to say ``%?string'' +which specifies a job whose text contains +.I string, +if there is only one such job. +.PP +The shell also maintains a notion of the current and previous jobs. +In output pertaining to jobs, the current job is marked with a ``+'' +and the previous job with a ``\-''. The abbreviation ``%+'' refers +to the current job and ``%\-'' refers to the previous job. For close +analogy with the +.I history +mechanism, +``%%'' is also a synonym for the current job. +.PP +.B "Status reporting." +.PP +This shell learns immediately whenever a process changes state. +It normally informs you whenever a job becomes blocked so that +no further progress is possible, but only just before it prints +a prompt. This is done so that it does not otherwise disturb your work. +If, however, you set the shell variable +.I notify, +the shell will notify you immediately of changes of status in background +jobs. +There is also a shell command +.I notify +which marks a single process so that its status changes will be immediately +reported. By default +.I notify +marks the current process; +simply say ``notify'' after starting a background job to mark it. +.PP +When you try to leave the shell while jobs are stopped, you will +be warned that ``You have stopped jobs.'' You may use the ``jobs'' +command to see what they are. If you do this or immediately try to +exit again, the shell will not warn you a second time, and the suspended +jobs will be unmercifully terminated. +.PP +.B "New builtin commands." +.HP 5 +.B bg +.br +.ns +.HP 5 +\fBbg\ %\fRjob\ ... +.br +Puts the current or specified jobs into the background, continuing them +if they were stopped. +.HP 5 +.B fg +.br +.ns +.HP 5 +\fBfg\ %\fRjob\ ... +.br +Brings the current or specified jobs into the foreground, continuing them if +they were stopped. +.HP 5 +.B jobs +.br +.ns +.HP 5 +.B "jobs \-l" +.br +Lists the active jobs; given the +.B \-l +options lists process id's in addition to the normal information. +.HP 5 +\fBkill %\fRjob +.br +.ns +.HP 5 +\fBkill\ \-\fRsig\ \fB%\fRjob\ ... +.br +.ns +.HP 5 +\fBkill\fR\ pid +.br +.ns +.HP 5 +\fBkill\ \-\fRsig\ pid\ ... +.br +.ns +.HP 5 +\fBkill\ \-l\fR +.br +Sends either the TERM (terminate) signal or the +specified signal to the specified jobs or processes. +Signals are either given by number or by names (as given in +.I /usr/include/signal.h, +stripped of the prefix ``SIG''). +The signal names are listed by ``kill \-l''. +There is no default, saying just `kill' does not +send a signal to the current job. +If the signal being sent is TERM (terminate) or HUP (hangup), +then the job or process will be sent a CONT (continue) signal as well. +.HP 5 +.B notify +.br +.ns +.HP 5 +\fBnotify\ %\fRjob\ ... +.br +Causes the shell to notify the user asynchronously when the status of the +current or specified jobs changes; normally notification is presented +before a prompt. All jobs are marked ``notify'' if the shell variable +``notify'' is set. +.HP 5 +\fBstop\ %\fRjob\ ... +.br +Stops the specified job which is executing in the background. +.HP 5 +\fB%\fRjob +.br +Brings the specified job into the foreground. +.HP 5 +\fB%\fRjob \fB&\fR +.br +Continues the specified job in the background. +.br +.ne 5 +.PP +.B "Process limitations." +.PP +The shell provides access to an experimental facility for limiting +the consumption by a single process of system resources. +The following commands control this facility: +.HP 5 +\fBlimit\fR \fIresource\fR \fImaximum-use\fR +.HP 5 +\fBlimit\fR \fIresource\fR +.br +.ns +.HP +\fBlimit\fR +.br +Limits the consumption by the current process and each process +it creates to not individually exceed \fImaximum-use\fR on the +specified \fIresource\fR. If no \fImaximum-use\fR is given, then +the current limit is printed; if no \fIresource\fR is given, then +all limitations are given. +.IP +Resources controllable currently include \fIcputime\fR (the maximum +number of cpu-seconds to be used by each process), \fIfilesize\fR +(the largest single file which can be created), \fIdatasize\fR +(the maximum growth of the data+stack region via +.IR sbrk (2) +beyond the end of the program text), \fIstacksize\fR (the maximum +size of the automatically-extended stack region), and \fIcoredumpsize\fR +(the size of the largest core dump that will be created). +.IP +The \fImaximum-use\fR may be given as a (floating point or integer) +number followed by a scale factor. For all limits other than \fIcputime\fR +the default scale is ``k'' or ``kilobytes'' (1024 bytes); +a scale factor of ``m'' or ``megabytes'' may also be used. +For cputime the default scaling is ``seconds'', while ``m'' for minutes +or ``h'' for hours, or a time of the form ``mm:ss'' giving minutes +and seconds may be used. +.IP +For both \fIresource\fR names and scale factors, unambiguous prefixes +of the names suffice. +.HP 5 +\fBunlimit\fR \fIresource\fR +.br +.ns +.HP 5 +\fBunlimit\fR +.br +Removes the limitation on \fIresource\fR. If no \fIresource\fR +is specified, then all \fIresource\fR limitations are removed. +.ne 5 +.PP +.B "Directory stack." +.PP +This shell now keeps track of the current directory (which is kept +in the variable +.I cwd) +and also maintains a stack of directories, which is printed by the +command +.I dirs. +You can change to a new directory and push down the old directory +stack by using the command +.I pushd +which is otherwise like the +.I chdir +command, changing to its argument. +You can pop the directory stack by saying +.I popd. +Saying +.I pushd +with no arguments exchanges the top two elements of the directory stack. +The elements of the directory stack are numbered from 1 starting at the top. +Saying +.I pushd +with a argument ``+\fIn\fR'' rotates the directory stack to make that entry +in the stack be at the top and changes to it. +Giving +.I popd +a ``+\fIn\fR'' argument eliminates that argument from the directory stack. +.PP +.B "Miscellaneous." +.PP +This shell imports the environment variable USER into the variable +.I user, +TERM into +.I term, +and +HOME into +.I home, +and exports these back into the environment whenever the normal +shell variables are reset. +The environment variable PATH is likewise handled; it is not +necessary to worry about its setting other than in the file +.I \&.cshrc +as inferior +.I csh +processes will import the definition of +.I path +from the environment, and re-export it if you then change it. +(It could be set once in the +.I \&.login +except that commands over the Berknet would not +see the definition.) +.PP +There are new commands +.I eval, +which is like the eval of the Bourne shell +.IR sh (1), +and useful with +.IR tset (1), +and +.I suspend +which stops a shell (as though a ^Z had stopped it; since +shells normally ignore ^Z signals, this command is necessary.) +.PP +There is a new variable +.I cdpath; +if set, then each directory in +.I cdpath +will be searched for a directory named in a +.I chdir +command if there is no such subdirectory of the current directory. +.PP +An +.I unsetenv +command removing environment variables has been added. +.PP +There is a new ``:'' modifier ``:e'', which yields the extension +portion of a filename. Thus if ``$a'' is ``file.c'', ``$a:e'' is ``c''. +.PP +There are two new operators in shell expressions ``!~'' and ``=~'' which +are like the string operations ``!='' and ``=='' except that the right +hand side is a +.I pattern +(containing, e.g. ``*''s, ``?''s and instances of ``[...]'') +against which the left hand operand is matched. This reduces the +need for use of the +.I switch +statement in shell scripts when all that is really needed is pattern matching. +.PP +The form ``$<'' is new, and is replaced by a line from the standard +input, with no further interpretation thereafter. It may therefore +be used to read from the keyboard in a shell script. +.SH "SEE ALSO" +csh(1), killpg(2), sigsys(2), signal(2), jobs(3), sigset(3), tty(4) +.SH BUGS +Command sequences of the form ``a ; b ; c'' are not handled gracefully +when stopping is attempted. If you suspend ``b'', the shell will then +immediately execute ``c''. This is especially noticeable if this +expansion results from an +.I alias. +It suffices to place the sequence of commands in ()'s to force it to +a subshell, i.e. ``( a ; b ; c )'', but see the next bug. +.PP +Shell builtin functions are not stoppable/restartable. +.PP +Control over output is primitive; +perhaps this will inspire someone to work on a good virtual +terminal interface. In a virtual terminal interface much more +interesting things could be done with output control. |