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diff --git a/pkg/language/doc/set.hlp b/pkg/language/doc/set.hlp new file mode 100644 index 00000000..1b552eb4 --- /dev/null +++ b/pkg/language/doc/set.hlp @@ -0,0 +1,82 @@ +.help set,reset Apr87 language +.ih +NAME +.nf + set -- set the value of an IRAF environment variable +reset -- reset (overwrite) the value of an IRAF environment variable +.fi +.ih +USAGE +.nf +set [varname = valuestring] +reset [varname = valuestring] +.fi +.ih +PARAMETERS +.ls varname +The environment variable to be defined or set. +.le +.ls valuestring +The new string value of the environment variable. +.le +.ih +DESCRIPTION +The CL maintains a list of environment variables, each of which consists +of a keyword = value pair. The \fIset\fR and \fIreset\fR operators are used +to define new environment variables, or to set new values for old environment +variables. The two operators are equivalent with the exception that if the +named environment variable is already defined, \fIset\fR will push a new, +temporary value for the variable, whereas \fIreset\fR will overwrite the most +recent definition of the variable. Environment variables may be examined +using the \fIshow\fR task or the \fIenvget\fR intrinsic function. + +A particular use for the environment variables is in the definition +of IRAF logical names for directories. If an environment variable is set to +a string corresponding to a system-dependent directory name, +then the environment variable may then be used within the CL to +refer to that directory. + +For example, + +.nf + set testdir = "/usr/iraf/testdir" # Unix + set testdir = "dua2:[iraf.testdir]" # VMS + task tst1 = testdir$tst1.cl +.fi + +New IRAF logicals may be defined in terms or existing IRAF logical names, +i.e., logical names are recursively expanded. + +.nf + set subdir1 = testdir$subdir1/ + task tst2 = subdir1$tst2.e +.fi + +If the \fIset\fR command is entered without any arguments the current +environment list is printed in the reverse of the order in which the +definitions were made. If a variable has been redefined both the +final and original definition are shown. The \fIshow\fR command can be +used to show only the current value. +.ih +EXAMPLES +1. Define the data directory "dd" on a remote node, and call \fIimplot\fR +to make plots of an image which resides in the remote directory. + +.nf + cl> set dd = lyra!/u2/me/data + cl> implot dd$picture +.fi + +2. Temporarily change the value of the variable \fIprinter\fR. The new +value is discarded when the \fIbye\fR is entered. + +.nf + cl> cl + cl> set printer = qms + ... + cl> bye +.fi +.ih +SEE ALSO +show, envget +.endhelp |