Can colorized output be captured via shell redirect? [duplicate]

Question

Various bash commands I use -- fancy diffs, build scripts, etc, produce lots of color output.

When I redirect this output to a file, and then cat or less the file later, the colorization is gone -- presumably b/c the act of redirecting the output stripped out the color codes that tell the terminal to change colors.

Is there a way to capture colorized output, including the colorization?

Answer 1

One way to capture colorized output is with the script command. Running script will start a bash session where all of the raw output is captured to a file (named typescript by default).

Answer 2

Redirecting doesn't strip colors, but many commands will detect when they are sending output to a terminal, and will not produce colors by default if not. For example, on Linux ls --color=auto (which is aliased to plain ls in a lot of places) will not produce color codes if outputting to a pipe or file, but ls --color will. Many other tools have similar override flags to get them to save colorized output to a file, but it's all specific to the individual tool.

Even once you have the color codes in a file, to see them you need to use a tool that leaves them intact. less has a -r flag to show file data in "raw" mode; this displays color codes. edit: Slightly newer versions also have a -R flag which is specifically aware of color codes and displays them properly, with better support for things like line wrapping/trimming than raw mode because less can tell which things are control codes and which are actually characters going to the screen.