Show special characters in Unix while using 'less' Command

linux unix command
Kingsly picture Kingsly · Aug 4, 2011 · Viewed 133.2k times · Source

I would like to know how to view special characters while using 'less' command. For instance I want to see the non-printable characters with a special notation. For instance in 'vi' editor I use "set list on" to see the line termination characters represented by dollar '$' character. Similarly I would want to do this using 'less' command.

I referred Unix less manual, but to no avail.

Answer

shellter picture shellter · Aug 4, 2011

less will look in its environment to see if there is a variable named LESS

You can set LESS in one of your ~/.profile (.bash_rc, etc, etc) and then anytime you run less from the comand line, it will find the LESS.

Try adding this

export LESS="-CQaix4"

This is the setup I use, there are some behaviors embedded in that may confuse you, so you can find out about what all of these mean from the help function in less, just tap the 'h' key and nose around, or run less --help.

Edit:

I looked at the help, and noticed there is also an -r option 

-r  -R  ....  --raw-control-chars  --RAW-CONTROL-CHARS
                Output "raw" control characters.

I agree that cat may be the most exact match to your stated needs.

cat -vet file | less

Will add '$' at end of each line and convert tab char to visual '^I'. 

cat --help
   (edited)
    -e                       equivalent to -vE
    -E, --show-ends          display $ at end of each line
    -t                       equivalent to -vT
    -T, --show-tabs          display TAB characters as ^I
    -v, --show-nonprinting   use ^ and M- notation, except for LFD and TAB

I hope this helps.

Related questions

How can I recall the argument of the previous bash command?

Is there a way in Bash to recall the argument of the previous command? I usually do vi file.c followed by gcc file.c. Is there a way in Bash to recall the argument of the previous command?

Read More
Using grep and ls -a commands

Using an ls –a and grep, how would you list the name of all of the files in /usr starting with the letter p or the letter r or the letter s using a single grep command? would this be …

Read More
What is that "total" in the very first line after ls -l?

What is the total in the output of ls -l? $ ls -l /etc total 3344 -rw-r--r-- 1 root root 15276 Oct 5 2004 a2ps.cfg -rw-r--r-- 1 root root 2562 Oct 5 2004 a2ps-site.cfg drwxr-xr-x 4 root root 4096 Feb 2 2007 acpi -rw-r--r-- 1 root root 48 Feb 8 2008 adjtime drwxr-xr-x 4 root …

Read More