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J. Doe
Asked: 2018-06-01 11:59:57 +0800 CST

Using a file to input variables in csh scripting

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unix%:~/tmp$ cat tmp.txt 
z=0.016728
NH=5.7E20
Center for spectra: 2:00:14.906, +31:25:45.826

I would like for the value of z to be set to a variable named $redsh, the value of NH to be $abun, and the values for the center to be $xc and $yc respectively.

How do I go about doing this?

command-line text-processing csh

2 Answers

  1. I’d use sed to replace the values from the file, add set and run eval on the whole thing:

    eval `sed 's/z=/set redsh=/;s/NH=/abun=/;s/.*: \(.*\), \(.*\)/xc=\1 yc=\2/' tmp.txt`

    Example run

    % unset redsh abun xc yc
% cat tmp.txt
z=0.016728
NH=5.7E20
Center for spectra: 2:00:14.906, +31:25:45.826
% eval `sed 's/z=/set redsh=/;s/NH=/abun=/;s/.*: \(.*\), \(.*\)/xc=\1 yc=\2/' tmp.txt`
% set
abun    5.7E20
…
redsh   0.016728
…
xc      2:00:14.906
yc      +31:25:45.826

    Note however that: You shouldn't use the C shell. Use the Bourne shell.

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  2. Read man csh;man grep;man cut;man awk;man tr and do something like 

    set redsh = "`grep -E '^z=' tmp.txt | cut -d= -f2`"
set abun = "`grep -E '^NH=' tmp.txt | cut -d= -f2`"
set xc = "`grep -E '^Center for spectra: ' tmp.txt | cut -d, -f1 | cut '-d ' -f4`"
set yc = "`grep -E '^Center for spectra: ' tmp.txt | cut -d, -f2 | tr -d ' '`"
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