shell usage tips

shell for loop

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for m in `cat m.md`;do echo $m;done

shell interop

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echo choice:$'\n' 1.a $'\n' 2.b $'\n' 3.b;read x;echo $x

Check files and process

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find /home/admin/logs/ -iname error.log | xargs cat

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find /home/admin/data2/zkLog/version-2 -mtime +3|xargs rm -f {}

Conditional judgment of awk value, and print

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cat /tmp/xxx | awk -F, '{source=substr($7,11,1);target=substr($8,14,1);if(source>target)print $7,$8}'

remove a character

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sed 's/\"//g'

Column summation with string handling

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cat /tmp/xxx |awk 'BEGIN{total=0}{v=substr($4,2);total+=v}END{print total}'