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| Chapter 5 The C Shell |

## if

    if

Begin a conditional statement. The simple format is:

>     if (expr) cmd

There are three other possible formats, shown side-by-side:

>     if (expr) then   if (expr) then   if (expr) then
>        cmds             cmds1             cmds1
>     endif            else              else if (expr) then
>                         cmds2             cmds2
>                      endif             else
>                                           cmds3
>                                        endif

In the simplest form, execute `cmd` if `expr` is true; otherwise do nothing (redirection still occurs; this is a bug). In the other forms, execute one or more commands. If `expr` is true, continue with the commands after then; if `expr` is false, branch to the commands after else (or after the else if and continue checking). For more examples, see "Expressions" earlier in this section, or shift or while.

### Example

Take a default action if no command-line arguments are given:

>     if ($#argv == 0) then
>        echo "No filename given.  Sending to Report."
>        set outfile = Report
>     else
>        set outfile = $argv[1]
>     endif

Reference: history |  | Reference: jobs