'\" '\" Copyright (c) 1993 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" SCCS: @(#) exec.n 1.12 96/03/25 20:13:20 '\" '\" The definitions below are for supplemental macros used in Tcl/Tk '\" manual entries. '\" '\" .AP type name in/out ?indent? '\" Start paragraph describing an argument to a library procedure. '\" type is type of argument (int, etc.), in/out is either "in", "out", '\" or "in/out" to describe whether procedure reads or modifies arg, '\" and indent is equivalent to second arg of .IP (shouldn't ever be '\" needed; use .AS below instead) '\" '\" .AS ?type? ?name? '\" Give maximum sizes of arguments for setting tab stops. Type and '\" name are examples of largest possible arguments that will be passed '\" to .AP later. If args are omitted, default tab stops are used. '\" '\" .BS '\" Start box enclosure. From here until next .BE, everything will be '\" enclosed in one large box. '\" '\" .BE '\" End of box enclosure. '\" '\" .CS '\" Begin code excerpt. '\" '\" .CE '\" End code excerpt. '\" '\" .VS ?br? '\" Begin vertical sidebar, for use in marking newly-changed parts '\" of man pages. If an argument is present, then a line break is '\" forced before starting the sidebar. '\" '\" .VE '\" End of vertical sidebar. '\" '\" .DS '\" Begin an indented unfilled display. '\" '\" .DE '\" End of indented unfilled display. '\" '\" .SO '\" Start of list of standard options for a Tk widget. The '\" options follow on successive lines, in four columns separated '\" by tabs. '\" '\" .SE '\" End of list of standard options for a Tk widget. '\" '\" .OP cmdName dbName dbClass '\" Start of description of a specific option. cmdName gives the '\" option's name as specified in the class command, dbName gives '\" the option's name in the option database, and dbClass gives '\" the option's class in the option database. '\" '\" .UL arg1 arg2 '\" Print arg1 underlined, then print arg2 normally. '\" '\" SCCS: @(#) man.macros 1.8 96/02/15 20:02:24 '\" '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b '\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ie !"\\$3"" \{\ .ta \\n()Au \\n()Bu \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. '\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out '\" # BS - start boxed text '\" # ^y = starting y location '\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. '\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. '\" # VS - start vertical sidebar '\" # ^Y = starting y location '\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$1"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. '\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. '\" # Special macro to handle page bottom: finish off current '\" # box/sidebar if in box/sidebar mode, then invoked standard '\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. '\" # DS - begin display .de DS .RS .nf .sp .. '\" # DE - end display .de DE .fi .RE .sp .. '\" # SO - start of list of standard options .de SO .SH "STANDARD OPTIONS" .LP .nf .ta 4c 8c 12c .ft B .. '\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\fBoptions\\fR manual entry for details on the standard options. .. '\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. '\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. '\" # CE - end code excerpt .de CE .fi .RE .. .de UL \\$1\l'|0\(ul'\\$2 .. .TH exec n 7.0 Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME exec \- Invoke subprocess(es) .SH SYNOPSIS \fBexec \fR?\fIswitches\fR? \fIarg \fR?\fIarg ...\fR? .BE .SH DESCRIPTION .PP This command treats its arguments as the specification of one or more subprocesses to execute. The arguments take the form of a standard shell pipeline where each \fIarg\fR becomes one word of a command, and each distinct command becomes a subprocess. .PP If the initial arguments to \fBexec\fR start with \fB\-\fR then .VS they are treated as command-line switches and are not part of the pipeline specification. The following switches are currently supported: .TP 13 \fB\-keepnewline\fR Retains a trailing newline in the pipeline's output. Normally a trailing newline will be deleted. .TP 13 \fB\-\|\-\fR Marks the end of switches. The argument following this one will be treated as the first \fIarg\fR even if it starts with a \fB\-\fR. .VE .PP If an \fIarg\fR (or pair of \fIarg\fR's) has one of the forms described below then it is used by \fBexec\fR to control the flow of input and output among the subprocess(es). Such arguments will not be passed to the subprocess(es). In forms .VS such as ``< \fIfileName\fR'' \fIfileName\fR may either be in a separate argument from ``<'' or in the same argument with no intervening space (i.e. ``<\fIfileName\fR''). .VE .TP 15 | Separates distinct commands in the pipeline. The standard output of the preceding command will be piped into the standard input of the next command. .TP 15 |& Separates distinct commands in the pipeline. Both standard output and standard error of the preceding command will be piped into the standard input of the next command. This form of redirection overrides forms such as 2> and >&. .TP 15 <\0\fIfileName\fR The file named by \fIfileName\fR is opened and used as the standard input for the first command in the pipeline. .TP 15 <@\0\fIfileId\fR .VS \fIFileId\fR must be the identifier for an open file, such as the return value from a previous call to \fBopen\fR. It is used as the standard input for the first command in the pipeline. \fIFileId\fR must have been opened for reading. .VE .TP 15 <<\0\fIvalue\fR \fIValue\fR is passed to the first command as its standard input. .TP 15 >\0\fIfileName\fR Standard output from the last command is redirected to the file named \fIfileName\fR, overwriting its previous contents. .TP 15 2>\0\fIfileName\fR .VS Standard error from all commands in the pipeline is redirected to the file named \fIfileName\fR, overwriting its previous contents. .TP 15 >&\0\fIfileName\fR Both standard output from the last command and standard error from all commands are redirected to the file named \fIfileName\fR, overwriting its previous contents. .VE .TP 15 >>\0\fIfileName\fR Standard output from the last command is redirected to the file named \fIfileName\fR, appending to it rather than overwriting it. .TP 15 2>>\0\fIfileName\fR .VS Standard error from all commands in the pipeline is redirected to the file named \fIfileName\fR, appending to it rather than overwriting it. .TP 15 >>&\0\fIfileName\fR Both standard output from the last command and standard error from all commands are redirected to the file named \fIfileName\fR, appending to it rather than overwriting it. .TP 15 >@\0\fIfileId\fR \fIFileId\fR must be the identifier for an open file, such as the return value from a previous call to \fBopen\fR. Standard output from the last command is redirected to \fIfileId\fR's file, which must have been opened for writing. .TP 15 2>@\0\fIfileId\fR \fIFileId\fR must be the identifier for an open file, such as the return value from a previous call to \fBopen\fR. Standard error from all commands in the pipeline is redirected to \fIfileId\fR's file. The file must have been opened for writing. .TP 15 >&@\0\fIfileId\fR \fIFileId\fR must be the identifier for an open file, such as the return value from a previous call to \fBopen\fR. Both standard output from the last command and standard error from all commands are redirected to \fIfileId\fR's file. The file must have been opened for writing. .VE .PP If standard output has not been redirected then the \fBexec\fR command returns the standard output from the last command in the pipeline. If any of the commands in the pipeline exit abnormally or are killed or suspended, then \fBexec\fR will return an error and the error message will include the pipeline's output followed by error messages describing the abnormal terminations; the \fBerrorCode\fR variable will contain additional information about the last abnormal termination encountered. If any of the commands writes to its standard error file and that standard error isn't redirected, then \fBexec\fR will return an error; the error message will include the pipeline's standard output, followed by messages about abnormal terminations (if any), followed by the standard error output. .PP If the last character of the result or error message is a newline then that character is normally deleted from the result or error message. This is consistent with other Tcl return values, which don't normally end with newlines. .VS However, if \fB\-keepnewline\fR is specified then the trailing newline is retained. .VE .PP If standard input isn't redirected with ``<'' or ``<<'' or ``<@'' then the standard input for the first command in the pipeline is taken from the application's current standard input. .PP If the last \fIarg\fR is ``&'' then the pipeline will be executed in background. .VS In this case the \fBexec\fR command will return a list whose elements are the process identifiers for all of the subprocesses in the pipeline. .VE The standard output from the last command in the pipeline will go to the application's standard output if it hasn't been redirected, and error output from all of the commands in the pipeline will go to the application's standard error file unless redirected. .PP The first word in each command is taken as the command name; tilde-substitution is performed on it, and if the result contains no slashes then the directories in the PATH environment variable are searched for an executable by the given name. If the name contains a slash then it must refer to an executable reachable from the current directory. No ``glob'' expansion or other shell-like substitutions are performed on the arguments to commands. .SH KEYWORDS execute, pipeline, redirection, subprocess