NAME

arg   –   ARG 2.3 for UNIX/Linux systems

SYNTAX

arg   [-m<#>]   [-c]   <inputs>   <template>   [marker]

DESCRIPTION

Arg is a program to facilitate writing long scripts, where the same command or set of commands need to be repeated for a large number of input values (e.g., a list of file names, image names, numeric constants, etc..). Using arg, one only needs to write a template for the script, in which the variable input is represented by a unique marker character (e.g., '&', '$', '%', '@') or character sequence (e.g., '$1', '$2', '%1', '%2', 'INFIL', 'OUFIL', 'X_IN', 'Y_IN') that is not used in the template script to denote anything other than such variable input.

inputs

is a file listing the values or strings, one per line, that need to be substituted wherever character sequence marker occurs in the template script.

template

is a file containing the template script.

marker (default is single character '&')

can be any single or multiple-character string acceptable to Fortran77 as such, and will be substituted by a character sequence read from inputs. Note, that some markers may need to be quoted to prevent interpretation by your shell.

For each line in inputs , arg will substitute the marker string(s) in template by the current replacement string from inputs in either one of three ways, selected by run-mode switch -m<#> , for integer <#>, as follows:

-m0      :   (default)

loop through inputs and replicate all lines in template and replace each occurance of the marker string by the replacement string

-m1      :

loop through both inputs and template one line at a time and copy each line in template while replacing the marker string(s) in that line by the replacement string. Note that inputs and template have to be of equal length.

-m<#> :

loop through inputs one line at a time and through template <#> lines at a time and copy each line per <#>-line block in template while replacing the marker string(s) in that block by the replacement string. Note that template needs to be <#> times the length of inputs.

Output is to the standard output (i.e., the screen) but may be redirected to any other device. For -m0 only, commented lines in the template (lines starting with a "#") may be skipped and omitted from the output using the -c run-mode switch. Use of this switch is currently not supported for the other modes.

If arg is invoked without any arguments or with invalid arguments, a short version of this man-page is printed.

EXAMPLES

1.   We constructed a super dark image and associated sigma image by combining the dark frames from several observing runs with the same CCD camera. For the individual runs we then construct master dark images by replacing pixels in a copy of that super dark that differ more than 3σ from the mean in a contemporaneous dark by values taken from that contemporaneous dark in order to account for systematic changes over time. The mean of the super dark frame is 0.183; the ampersands ('&') in "script.tem" will be replaced by the observing run identifier ('Nov01', 'Feb02', etc..) and the percentage signs ('%') in "expr.tem" will be replaced with a mean value of the dark frame of a run that will be determined on-the-fly. We will further assume that our programming environment will be NOAO's Image Reduction and Analysis Facility (IRAF).

Create a file "expr.tem" (command string/expression for task 'imcalc' in the 'stsdas' package) with the following contents:

   cl>  type expr.tem
      if ( abs( im1 - 0.183 - (im3 - % ) ) > 3*abs(im2) ) then
         im3
      else
         ( im1 - 0.183 + % )

Create the template script "script.tem" with the following contents:

   cl>  type script.tem
      imstat ("&/DARK.fits[256:768,256:768]", fields="mean",
             lower=INDEF, upper=INDEF, nclip=3, lsigma=3., usigma=3.,
             format-, > "tmp.stat")
      print ("!arg tmp.stat expr.tem '%' > imcalc.expr") | cl
      imcalc ("SUPERDARK,e_SUPERDARK,&/DARK",
	     "&/MASTERDARK", "@imcalc.expr")
      delete ("tmp.stat,imcalc.expr", yes, verify-)

Create an input list of the observing run identifier strings with the following contents:

   cl>  type runs.lis
      Nov01
      Feb02
      Apr02
      Jun02
      Oct02

Replicate the template script while substituting each occurance of marker character '&' with the current replacement string read from "runs.lis", then execute that script (after verifying it makes sense):

   cl>  !arg runs.lis script.tem '&' > script.cl
   cl>  type script.cl
   cl>  cl < script.cl




2.   Assume we retrieved a large (N≫1) number of image files from a telescope data archive and want to rename and move them:

   $>  cd /scratch/
   $>  \ls -1 0*.fits > /data/im.lis
   $>  cd /data/

We will use fitsheader, and awk and cut to retrieve the original object names (and to demonstrate the usage of arg), but any other means (e.g., from within IRAF or IDL, or listhead included in W.D. Pence's 'cfitsio' library) can be used as well; we'll also assume our shell is 'csh' or 'tcsh':

   $>  echo "fitsheader /scratch/& -k object | awk '{print $3}' | \
   >>>   cut -c2- >> name.lis" > getname.tem
   $>  arg -m0 im.lis getname.tem > getname
   $>  source getname
   $>  echo "\mv /scratch/$ /data/%" > rename.tem
   $>  arg -m0 im.lis rename.tem '$' > rename.1
   $>  arg -m1 name.lis rename.1 '%' > rename
   $>  source rename

So with few commands and without any editing one can complete tedious tasks like these quickly. Of course, this was a simple example (which might have been achieved even quicker using just some Unix magic), but for more complicated, multi-line scripts that would expand to thousands of lines of code, arg will be very efficient.

FILES

/usr/local/bin/arg

/usr/local/man/man1/arg.1

/usr/local/src/arg2.3/src/arg.f

SEE ALSO

narg

AUTHOR

R.A. Jansen <Rolf.Jansen@asu.edu>

COPYRIGHT

©1998–2013 R.A. Jansen/DinoSoft; The name 'arg' and one of the run-modes are based in part on earlier code by M. Franx.