Re: bash syntax
Am 29. Jul, 2021 schwätzte mick crane so:
moin moin nick,
I nicked this off some guy on the internet.
1 #!/bin/bash
2 count_file="scan_count.txt"
3 ct=`cat $count_file`
4 ((ct++))
5 scanimage > /home/mick/DATA/SCANS/scan-$ct.pnm
6 echo $ct > $count_file
What's the thing with the ct being in double brackets and not having the "$"
?
shell math.
Seach the bash man page for "ARITHMETIC EVALUATION"
In this case, it's adding one to the value that ct had.
3 Read the number in the file
4 Increment it by one
5 Run scanimage using the number in the file name
6 Write the new number to the file
scan_count.txt just is one line with a number.
It's tracking the number of iterations to create numbered filenames for
the scanimage output.
ciao,
der.hans
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