Repeat previous command

`↑ Shift` + `R`

All hotkeys for ImageJ

General Create new image or stack	`N`
General Create new text window	`↑ Shift` + `N`
General Create image from system clipboard	`↑ Shift` + `V`
General Open TIFF, GIF, JPEG, BMP, DICOM, FITS, etc.	`O`
General Open next image in folder	`↑ Shift` + `O`
General Opens "Blobs" example image	`↑ Shift` + `B`
General Close the active window	`W`
General Save active image in Tiff format	`S`
General Revert to saved version of image	`R`
General Print active image	`P`
General Undo last operation	`Z`
General Copy selection to internal clipboard and clear	`X`
General Copy selection to internal clipboard	`C`
General Paste contents of internal clipboard	`V`
General Erase selection to background color	`⬅ Backspace`
General Fill selection in foreground color	`F`
General Draw selection	`D`
General Invert image or selection	`↑ Shift` + `I`
General Select entire image	`A`
General Delete selection	`↑ Shift` + `A`
General Restore previous selection	`↑ Shift` + `E`
General Add selection to ROI Manager	`T`
General Adjust brightness and contrast	`↑ Shift` + `C`
General Adjust threshold levels	`↑ Shift` + `T`
General Display information about active image	`İ`
General Display image properties	`↑ Shift` + `P`
General Open Color Picker	`↑ Shift` + `K`
General Next hyperstack channel	`→`
General Previous hyperstack channel	`←`
General Reslice stack	`/`
General Start/stop stack animation	`\`
General Open "Channels" tool	`↑ Shift` + `Z`
General Next hyperstack slice	`Ctrl` + `→`
General Previous hyperstack slice	`Ctrl` + `←`
General Next hyperstack frame	`Alt` + `→`
General Previous hyperstack frame	`Alt` + `←`
General Crop active image or selection	`↑ Shift` + `X`
General Duplicate active image or selection	`↑ Shift` + `D`
General Scale image or selection	`E`
General Make image larger	`+`
General Make image larger	`↑`
General Make image smaller	`-`
General Make image smaller	`↓`
General Revert to original zoom level	`4`
General Zoom to 1:1	`5`
General 3x3 unweighted smoothing	`↑ Shift` + `S`
General Repeat previous command	`↑ Shift` + `R`
General Display statistics about active image or selection	`M`
General Display histogram of active image or selection	`H`
General Display density profile plot of current selection	`K`
General Select first gel lane	`1`
General Select next gel lane	`2`
General Plot gel lanes	`3`
General Install a macro set	`↑ Shift` + `M`
General Grab screenshot	`↑ Shift` + `G`
General List, find and launch commands	`L`
General Make all windows visible	`↑ Shift` + `F`
General Switch to next image window	`⭾ Tab`
General Bring "ImageJ" window to front	`⤶ Enter`