Linux Shell Scripting Cookbook - Third Edition

Getting rid of extra blank lines

Some text files contain two or more blank lines together. If you need to remove the extra blank lines, use the following syntax:

$ cat -s file

Consider the following example:

$ cat multi_blanks.txt
line 1


line 2
 


line 3
     



line 4

$ cat -s multi_blanks.txt # Squeeze adjacent blank lines
line 1
      
line 2
      
line 3

line 4

We can remove all blank lines with tr, as discussed in the Translating with tr recipe in this chapter.