dayid's ksh notes

Quickly familiarizing when coming from bash

Yes, an article on ksh shouldn't be about bash. My reality though reflets that 99% of the time if I'm talking about ksh it's because of someone who is familiar with bash asking a question, so here's the bare-minimum they're looking for (note: this presumes the default 'emacs' mode):

^p = previous command. Similar to hitting up-arrow in bash. Repeat to go further.
^n = next command. Similar to hitting down-arrow in bash. Repeat to go further.
^r = reverse-search history. Similar to ^r in bash.
fc = fix-command, run with no arguments, will open previous command in $FCEDIT (or ed if undefined)

fc, fix command

fc is "fix-command" and allows you to modify your previous commands. Direct from the ksh manual page which says it most simply:


It allows you to modify a previous command in an editor (ed by default). A brief example of fixing a previous command:

$ echo "Hello Woorld"
$ fc -l             # l, "list" commands you can fix
  1   echo "testing"
  2   echo "Hello Woorld"
# For example purposes:
$ fc 2 # This will use $FCEDIT to edit the command. When $FCEDIT exists, the buffer will be run.
  20                 # ed showing how many bytes the buffer is
  p                  # user input for ed to print the line
  echo "Hello Woorld"
  s/Woo/Wo           # using substitution to fix the mistyped "oo" to just "o"
  echo "Hello World" # ed automatically prints the line for you again
  wq                 # write/quit - the command will now run again.
$ echo "Hello World"
Don't want to use ed (default)? Set FCEDIT to your editor of choice and it will be used instead.

Setting multi-session history: if $HISTFILE is defined, it will be used. You can keep this per-session by using something like: HISTFILE=$HOME/.kshhist.$$ or cross-sessions using HISTFILE=$HOME/.ksh_history. This would normally be noted in ~/.profile

What I used to write this

@(#)PD KSH v5.2.14 99/07/13.2

OpenBSD 6.8 GENERIC.MP#407 i386