Linux Bash shell one practice : array if else
shell practice 1
1.require
A B C D
1 2 3 4
5 6 7 8
3 5 8 0
1 2 4 3
after handling:
T A B C D
A 1 2 3 4
B 5 6 7 8
C 3 5 8 0
D 1 2 4 3
1.first need read the first line as an array.
then append the element in the proper position for file;
oldifs=$IFS IFS=$‘\n‘; counter=0; cols=‘‘ for line in $(cat test.txt); do if [ $counter -eq 0 ]; then IFS=$‘ ‘ read -a cols <<< "$line"; echo ‘T ‘ $line > test_new.txt; IFS=$‘\n‘; else echo "${cols[counter-1]} " $line>>test_new.txt; fi let counter++; done; cat test_new.txt; IFS=$oldifs;
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