I have a big huge file e.g
chr1 1 G 300 chr1 2 A 500 chr1 3 C 200 chr4 1 T 35 chr4 2 G 400 chr4 3 C 435 chr3 1 G 300 chr3 2 A 500 chr3 3 C 200 chr3 1 T 35 chr3 2 G 400 chr6 3 C 435 chr6 4 A 223 chr6 5 T 400 chr6 6 G 300 I to split the file in multiple files by grouping the first column values e.g
File1.txt
chr1 1 G 300 chr1 2 A 500 chr1 3 C 200 file 3.txt
chr3 1 G 300 chr3 2 A 500 chr3 3 C 200 chr3 1 T 35 chr3 2 G 400 Awk solution:
awk '{ print > ("file" substr($1, 4) ".txt") }' file substr($1, 4) - extract substring from the 1st field value $1 starting from position 4Viewing results:
$ head file[0-9]*.txt ==> file1.txt <== chr1 1 G 300 chr1 2 A 500 chr1 3 C 200 ==> file3.txt <== chr3 1 G 300 chr3 2 A 500 chr3 3 C 200 chr3 1 T 35 chr3 2 G 400 ==> file4.txt <== chr4 1 T 35 chr4 2 G 400 chr4 3 C 435 ==> file6.txt <== chr6 3 C 435 chr6 4 A 223 chr6 5 T 400 chr6 6 G 300 