Turning multiple lines into one comma separated line [duplicate]

Using paste command:

paste -d, -s file

linux perl unix sed awk

aaabbbcccddd

cat file | xargs

aaa bbb ccc ddd

cat file | xargs | sed -e 's/ /,/g'

aaa,bbb,ccc,ddd

linux perl unix sed awk

There are many ways it can be achieved. The tool you use mostly depends on your own preference or experience.

Using tr command:

tr '\n' ',' < somefile

Using awk:

awk -F'\n' '{if(NR == 1) {printf $0} else {printf ","$0}}' somefile

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