Shell Command Line – Effect of a Lone Backtick at the End

You could use script (use -f to make sure it flushes every time) and you can have all the output in a file.

Use a terminal multiplexer (screen, tmux etc). For instance, for screen http://web.mit.edu/gnu/doc/html/screen_11.html#

Command: copy Enter copy/scrollback mode. This allows you to copy text from the current window and its history into the paste buffer. In this mode a vi-like full screen editor is active, with controls as outlined below.

Other terminal multiplexers surely have more advanced capabilities.

This is by design. Bash reads scripts in chunks. So it'll read a portion of the script, run any lines that it can, and then read the next chunk.

So you run into something like this:

• Bash reads the first 256 bytes (bytes 0-255) of the script.
• Within that first 256 bytes is a command that takes a while to run, and bash starts that command, waiting for it to exit.
• While the command is running, the script is updated, and the portion changed is after the 256 bytes it already read.
• When the command bash was running finishes, it continues reading the file, resuming from where it was, getting bytes 256-511.
• That portion of the script changed, but bash doesn't know that.

Where this becomes even more problematic is that if you edit anything before byte 256. Lets say you delete a couple of lines. Then the data in the script that was at byte 256, is now somewhere else, say at byte 156 (100 bytes earlier). Because of this, when bash continues reading, it's going to get what was originally 356.

This is just an example. Bash doesn't necessarily read 256 bytes at a time. I don't know exactly how much it reads at a time, but it doesn't matter, behavior is still the same.