taoky / colortee

A naive impl of `tee` with ANSI escape color codes specially handled

colortee

Colortee is a simple and naive program imitating UNIX tee. It outputs to tty preserving raw input, and to file with ANSI escape codes about colors filtered.

It supports appending to existing files (-append), and force outputting raw contents to files (-raw).

Build

go build

Examples

$ ls --color=always | ./colortee /tmp/test && hexdump -C /tmp/test
colortee
colortee.go
go.mod
README.md
00000000  63 6f 6c 6f 72 74 65 65  0a 63 6f 6c 6f 72 74 65  |colortee.colorte|
00000010  65 2e 67 6f 0a 67 6f 2e  6d 6f 64 0a 52 45 41 44  |e.go.go.mod.READ|
00000020  4d 45 2e 6d 64 0a                                 |ME.md.|
00000026
$ ls --color=always | ./colortee -raw /tmp/test && hexdump -C /tmp/test
colortee
colortee.go
go.mod
README.md
00000000  1b 5b 30 6d 1b 5b 30 31  3b 33 32 6d 63 6f 6c 6f  |.[0m.[01;32mcolo|
00000010  72 74 65 65 1b 5b 30 6d  0a 63 6f 6c 6f 72 74 65  |rtee.[0m.colorte|
00000020  65 2e 67 6f 0a 67 6f 2e  6d 6f 64 0a 52 45 41 44  |e.go.go.mod.READ|
00000030  4d 45 2e 6d 64 0a                                 |ME.md.|
00000036
$ ls --color=always | ./colortee -append /tmp/test && hexdump -C /tmp/test
colortee
colortee.go
go.mod
README.md
00000000  1b 5b 30 6d 1b 5b 30 31  3b 33 32 6d 63 6f 6c 6f  |.[0m.[01;32mcolo|
00000010  72 74 65 65 1b 5b 30 6d  0a 63 6f 6c 6f 72 74 65  |rtee.[0m.colorte|
00000020  65 2e 67 6f 0a 67 6f 2e  6d 6f 64 0a 52 45 41 44  |e.go.go.mod.READ|
00000030  4d 45 2e 6d 64 0a 63 6f  6c 6f 72 74 65 65 0a 63  |ME.md.colortee.c|
00000040  6f 6c 6f 72 74 65 65 2e  67 6f 0a 67 6f 2e 6d 6f  |olortee.go.go.mo|
00000050  64 0a 52 45 41 44 4d 45  2e 6d 64 0a              |d.README.md.|
0000005c
$ ls --color=auto | ./colortee -raw /tmp/test && hexdump -C /tmp/test
colortee
colortee.go
go.mod
README.md
00000000  63 6f 6c 6f 72 74 65 65  0a 63 6f 6c 6f 72 74 65  |colortee.colorte|
00000010  65 2e 67 6f 0a 67 6f 2e  6d 6f 64 0a 52 45 41 44  |e.go.go.mod.READ|
00000020  4d 45 2e 6d 64 0a                                 |ME.md.|
00000026
$ unbuffer ls --color=auto | ./colortee -raw /tmp/test && hexdump -C /tmp/test
colortee  colortee.go  go.mod  README.md
00000000  1b 5b 30 6d 1b 5b 30 31  3b 33 32 6d 63 6f 6c 6f  |.[0m.[01;32mcolo|
00000010  72 74 65 65 1b 5b 30 6d  20 20 63 6f 6c 6f 72 74  |rtee.[0m  colort|
00000020  65 65 2e 67 6f 20 20 67  6f 2e 6d 6f 64 20 20 52  |ee.go  go.mod  R|
00000030  45 41 44 4d 45 2e 6d 64  0a                       |EADME.md.|
00000039

As you can see, you can use unbuffer from package expect to trick programs to forcely output colors even they don't provide an option. You can install expect with your system package manager. For example, you can run

sudo apt install expect

to install expect in Debian/Ubuntu.

Reference

Wikipedia - Tee (Command)