使用过 .xmodmap,重启后就失效，添加到rc.local也不管用，后来通过在xorg里配置成功。

更改xorg里的键盘配置，增加Option "XkbOptions" "caps:swapescape"

我用的archlinux在/etc/X11/xorg.conf.d/00-keyboard.conf ，有些可能在 /etc/X11/xorg.conf

一个可能的键盘字段类似下面这样

Section "InputClass"

        Identifier "system-keyboard"

        MatchIsKeyboard "on"

	Option "XkbOptions" "caps:swapescape"

        Option "XkbLayout" "cn"

        Option "XkbModel" "pc105"

EndSection

类似的命令可以在/usr/share/X11/xkb/rules/xorg.lst 里找到，比如

  caps:internal        Caps Lock uses internal capitalization; Shift "pauses" Caps Lock

  caps:internal_nocancel Caps Lock uses internal capitalization; Shift does not affect Caps Lock

  caps:shift           Caps Lock acts as Shift with locking; Shift "pauses" Caps Lock

  caps:shift_nocancel  Caps Lock acts as Shift with locking; Shift does not affect Caps Lock

  caps:capslock        Caps Lock toggles normal capitalization of alphabetic characters

  caps:shiftlock       Caps Lock toggles ShiftLock (affects all keys)

  caps:swapescape      Swap ESC and Caps Lock

  caps:escape          Make Caps Lock an additional Esc

  caps:backspace       Make Caps Lock an additional Backspace

  caps:super           Make Caps Lock an additional Super

  caps:hyper           Make Caps Lock an additional Hyper

  caps:menu            Make Caps Lock an additional Menu key

  caps:numlock         Make Caps Lock an additional Num Lock