garbled ls -l output when piped with less

[Prasad]

Running "ls -l | less" shows lot of garbled output.

Attaching screenshot.

[Prasad]

in the list of default aliases "ls" is aliased as

alias ls="ls --color"

In the source file of ls "src/bin/coreutils/src/ls.c"

1877         case COLOR_OPTION:
1878           {
1879             int i;
1880             if (optarg)
1881               i = XARGMATCH ("--color", optarg, color_args, color_types);
1882             else
1883               /* Using --color with no argument is equivalent to using
1884                  --color=always.  */
1885               i = color_always;
1886 
1887             print_with_color = (i == color_always
1888                                 || (i == color_if_tty
1889                                     && isatty (STDOUT_FILENO)));

Therefore, when ls is used with --color argument, it is always treated as ls --color="always", thus it ignores the isatty(STDOUT_FILENO) call and sets print_with_color = 1

As a result, even though "ls" output is redirected to a file, all the coloring scheme is still applied, resulting garbled characters added into the file.

So the fix is

$ git diff
diff --git a/data/etc/profile b/data/etc/profile
index a654808..e61bbc8 100644
--- a/data/etc/profile
+++ b/data/etc/profile
@@ -24,7 +24,7 @@ export LC_COLLATE=$LC_MESSAGES
 export LC_CTYPE=$LC_MESSAGES
 export LC_MONETARY=$LC_NUMERIC
 
-alias ls="ls --color"
+alias ls="ls --color=auto"
 alias ll="ls -lA"
 alias la="ls -A"
 alias m="more"

[Prasad]

Attaching a patch which fixes the problem

[scottmc]

Also semi-related to this, is track ticket #4494 which has a possible fix for poor default colors for ls --color

[leavengood]

Taking ownership.

[leavengood]

Patch applied in hrev44676. Thanks!

[diver]

Thanks! This one was annoying.

[korli]

As explained in #9044 this kind of customization should go in a specific /etc/profile.d/ script.