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BUILTIN(1)             DragonFly General Commands Manual            BUILTIN(1)

NAME

builtin, !, %, ., :, @, [, {, }, alias, alloc, bg, bind, bindkey, break, breaksw, builtins, case, cd, chdir, command, complete, continue, default, dirs, do, done, echo, echotc, elif, else, end, endif, endsw, esac, eval, exec, exit, export, false, fc, fg, filetest, fi, for, foreach, getopts, glob, goto, hash, hashstat, history, hup, if, jobid, jobs, kill, let, limit, local, log, login, logout, ls-F, nice, nohup, notify, onintr, popd, printenv, printf, pushd, pwd, read, readonly, rehash, repeat, return, sched, set, setenv, settc, setty, setvar, shift, source, stop, suspend, switch, telltc, termname, test, then, time, times, trap, true, type, ulimit, umask, unalias, uncomplete, unhash, unlimit, unset, unsetenv, until, wait, where, which, while, wordexp -- shell built-in commands

SYNOPSIS

See the built-in command description in the appropriate shell manual page.

DESCRIPTION

Shell builtin commands are commands that can be executed within the run- ning shell's process. Note that, in the case of csh(1) builtin commands, the command is executed in a subshell if it occurs as any component of a pipeline except the last. If a command specified to the shell contains a slash `/', the shell will not execute a builtin command, even if the last component of the speci- fied command matches the name of a builtin command. Thus, while specify- ing ``echo'' causes a builtin command to be executed under shells that support the echo builtin command, specifying ``/bin/echo'' or ``./echo'' does not. While some builtin commands may exist in more than one shell, their oper- ation may be different under each shell which supports them. Below is a table which lists shell builtin commands, the standard shells that sup- port them and whether they exist as standalone utilities. Only builtin commands for the csh(1) and sh(1) shells are listed here. Consult a shell's manual page for details on the operation its builtin commands. Beware that the sh(1) manual page, at least, calls some of these commands ``built-in commands'' and some of them ``reserved words''. Users of other shells may need to consult an info(1) page or other sources of documentation. Commands marked ``No**'' under External do exist externally, but are implemented as scripts using a builtin command of the same name. Command External csh(1) sh(1) ! No No Yes % No Yes No . No No Yes : No Yes Yes @ No Yes No [ Yes No Yes { No No Yes } No No Yes alias No** Yes Yes alloc No Yes No bg No** Yes Yes bind No No Yes bindkey No Yes No break No Yes Yes breaksw No Yes No builtin No No Yes builtins No Yes No case No Yes Yes cd No** Yes Yes chdir No Yes Yes command No** No Yes complete No Yes No continue No Yes Yes default No Yes No dirs No Yes No do No No Yes done No No Yes echo Yes Yes Yes echotc No Yes No elif No No Yes else No Yes Yes end No Yes No endif No Yes No endsw No Yes No esac No No Yes eval No Yes Yes exec No Yes Yes exit No Yes Yes export No No Yes false Yes No Yes fc No** No Yes fg No** Yes Yes filetest No Yes No fi No No Yes for No No Yes foreach No Yes No getopts No** No Yes glob No Yes No goto No Yes No hash No No Yes hashstat No Yes No history No Yes No hup No Yes No if No Yes Yes jobid No No Yes jobs No** Yes Yes kill Yes Yes Yes let No No Yes limit No Yes No local No No Yes log No Yes No login Yes Yes No logout No Yes No ls-F No Yes No nice Yes Yes No nohup Yes Yes No notify No Yes No onintr No Yes No popd No Yes No printenv Yes Yes No printf Yes No Yes pushd No Yes No pwd Yes No Yes read No** No Yes readonly No No Yes rehash No Yes No repeat No Yes No return No No Yes sched No Yes No set No Yes Yes setenv No Yes No settc No Yes No setty No Yes No setvar No No Yes shift No Yes Yes source No Yes No stop No Yes No suspend No Yes No switch No Yes No telltc No Yes No termname No Yes No test Yes No Yes then No No Yes time Yes Yes No times No No Yes trap No No Yes true Yes No Yes type No No Yes ulimit No No Yes umask No** Yes Yes unalias No** Yes Yes uncomplete No Yes No unhash No Yes No unlimit No Yes No unset No Yes Yes unsetenv No Yes No until No No Yes wait No** Yes Yes where No Yes No which Yes Yes No while No Yes Yes wordexp No No Yes

SEE ALSO

csh(1), echo(1), false(1), info(1), kill(1), login(1), nice(1), nohup(1), printenv(1), printf(1), pwd(1), sh(1), test(1), time(1), true(1), which(1)

HISTORY

The builtin manual page first appeared in FreeBSD 3.4.

AUTHORS

This manual page was written by Sheldon Hearn <sheldonh@FreeBSD.org>. DragonFly 3.5 May 18, 2012 DragonFly 3.5 switch(n) Tcl Built-In Commands switch(n) ______________________________________________________________________________

NAME

switch - Evaluate one of several scripts, depending on a given value

SYNOPSIS

switch ?options? string pattern body ?pattern body ...? switch ?options? string {pattern body ?pattern body ...?} ______________________________________________________________________________

DESCRIPTION

The switch command matches its string argument against each of the pattern arguments in order. As soon as it finds a pattern that matches string it evaluates the following body argument by passing it recursively to the Tcl interpreter and returns the result of that evaluation. If the last pattern argument is default then it matches anything. If no pattern argument matches string and no default is given, then the switch command returns an empty string. If the initial arguments to switch start with - then they are treated as options unless there are exactly two arguments to switch (in which case the first must the string and the second must be the pattern/body list). The following options are currently supported: -exact Use exact matching when comparing string to a pattern. This is the default. -glob When matching string to the patterns, use glob-style matching (i.e. the same as implemented by the string match command). -regexp When matching string to the patterns, use regular expression matching (as described in the re_syntax reference page). -nocase Causes comparisons to be handled in a case-insensitive manner. -matchvar varName This option (only legal when -regexp is also specified) specifies the name of a variable into which the list of matches found by the regular expression engine will be written. The first element of the list written will be the overall substring of the input string (i.e. the string argument to switch) matched, the second element of the list will be the substring matched by the first capturing parenthesis in the regular expression that matched, and so on. When a default branch is taken, the variable will have the empty list written to it. This option may be specified at the same time as the -indexvar option. -indexvar varName This option (only legal when -regexp is also specified) specifies the name of a variable into which the list of indices referring to matching substrings found by the regular expression engine will be written. The first element of the list written will be a two-element list specifying the index of the start and index of the first character after the end of the overall substring of the input string (i.e. the string argument to switch) matched, in a similar way to the -indices option to the regexp can obtain. Similarly, the second element of the list refers to the first capturing parenthesis in the regular expression that matched, and so on. When a default branch is taken, the variable will have the empty list written to it. This option may be specified at the same time as the -matchvar option. -- Marks the end of options. The argument following this one will be treated as string even if it starts with a -. This is not required when the matching patterns and bodies are grouped together in a single argument. Two syntaxes are provided for the pattern and body arguments. The first uses a separate argument for each of the patterns and commands; this form is convenient if substitutions are desired on some of the patterns or commands. The second form places all of the patterns and commands together into a single argument; the argument must have proper list structure, with the elements of the list being the patterns and commands. The second form makes it easy to construct multi-line switch commands, since the braces around the whole list make it unnecessary to include a backslash at the end of each line. Since the pattern arguments are in braces in the second form, no command or variable substitutions are performed on them; this makes the behavior of the second form different than the first form in some cases. If a body is specified as "-" it means that the body for the next pattern should also be used as the body for this pattern (if the next pattern also has a body of "-" then the body after that is used, and so on). This feature makes it possible to share a single body among several patterns. Beware of how you place comments in switch commands. Comments should only be placed inside the execution body of one of the patterns, and not intermingled with the patterns.

EXAMPLES

The switch command can match against variables and not just literals, as shown here (the result is 2): set foo "abc" switch abc a - b {expr {1}} $foo {expr {2}} default {expr {3}} Using glob matching and the fall-through body is an alternative to writing regular expressions with alternations, as can be seen here (this returns 1): switch -glob aaab { a*b - b {expr {1}} a* {expr {2}} default {expr {3}} } Whenever nothing matches, the default clause (which must be last) is taken. This example has a result of 3: switch xyz { a - b { # Correct Comment Placement expr {1} } c { expr {2} } default { expr {3} } } When matching against regular expressions, information about what exactly matched is easily obtained using the -matchvar option: switch -regexp -matchvar foo -- $bar { a(b*)c { puts "Found [string length [lindex $foo 1]] 'b's" } d(e*)f(g*)h { puts "Found [string length [lindex $foo 1]] 'e's and\ [string length [lindex $foo 2]] 'g's" } }

SEE ALSO

for(n), if(n), regexp(n)

KEYWORDS

switch, match, regular expression Tcl 8.5 switch(n)

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