I have a file with different record length. The file as to be converted into fixed length by appending spaces at the end of record. The length should be calculated based on the record with maximum length in the file.

If the length is less than the max length, the spaces should be appended before the new line character of that record.

 
Input File:
123
12345
1234
 
Output file:
123  
12345
1234 
 
Here the max record length is 5

awk 'NR==FNR{if(length($0) > maxlen){maxlen=length($0)}next}
{printf "|%-"maxlen"s|\n",$0}' file1.txt file1.txt

This is another way of doing it with awk which works for me:

awk 'BEGIN{while((getline f<FILENAME)>0){if(length(f)>l)l=length(f)}}{printf "%-"l"s\n",$0}' file

The command is working fine but when i redirect the output to a file at the actual end of record i am able to see Control M(^M) charater.

 
awk 'NR==FNR{if(length($0) > maxlen){maxlen=length($0)}next}
{printf "%-"maxlen"s\n",$0}' file1.txt file1.txt > file2.txt
 
Output file: file2.txt
123^M<2space>
12345^M
1234^M<1space>

 
awk 'BEGIN{while((getline f<FILENAME)>0){if(length(f)>l)l=length(f)}}{printf "%-"l"s\n",$0}' file

expression for `<' redirection has null string value

You need to use files that are in unix-format, not DOS-format. To convert:

tr -d '\r' < infile > outfile