Linux Shell Scripting Cookbook - Third Edition

Sorting according to keys or columns

We can use a column with sort if the input data is formatted like this:

$ cat data.txt
1  mac    2000
2  winxp    4000
3  bsd    1000
4  linux    1000

We can sort this in many ways; currently it is sorted numerically, by the serial number (the first column). We can also sort by the second or third column.

The -k option specifies the characters to sort by. A single digit specifies the column. The -r option specifies sorting in reverse order. Consider this example:

# Sort reverse by column1
$ sort -nrk 1  data.txt
4  linux    1000 
3  bsd    1000 
2  winxp    4000 
1  mac    2000 
# -nr means numeric and reverse

# Sort by column 2
$ sort -k 2  data.txt
3  bsd    1000 
4  linux    1000 
1  mac    2000 
2  winxp    4000

Always be careful about the -n ...