Bash command history editing multiple lines

bashcommand history

Over many years I used ksh. I like the possibility to use Esc v in command history to call the editor "vi". If this command in the history was spread over many lines – for example because of a while loop – "vi" shows this history also over many lines. With this feature it is easy possible to write complex statements without writing the input to a file.

Years ago I changes to bash. It has the same possibility with default shortcut Ctrl–X Ctrl–E. The slightly difference is that bash is merging all lines to one long line delimited with a semicolon. Syntax is still correct but we lose readability.

So what I am doing, I am calling ksh, if I see the commands become complex.

Is there a way to configure bash in a way not to merge the lines of the history and act as ksh is doing it?

Any help is welcome.

Best Answer

Use:

shopt -s lithist

lithist
If set, and the cmdhist option is enabled, multi-line commands are saved to the history with embedded newlines rather than using semicolon separators where possible.

I suspect the reason this isn't enabled by default is because people often use commands like history | grep something to find history entry numbers. If a history entry is split across multiple lines, the line that matches grep won't always contain the entry number.

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bash – Preserve Bash History in Multiple Terminal Windows

Add the following to your ~/.bashrc:

# Avoid duplicates
HISTCONTROL=ignoredups:erasedups
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend

# After each command, append to the history file and reread it
PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND$'\n'}history -a; history -c; history -r"

Bash – History command inside bash script

Bash disables history in noninteractive shells by default, but you can turn it on.

#!/bin/bash
HISTFILE=~/.bash_history
set -o history
history | tail …

But if you're trying to monitor activity on that server, the shell history is useless (it's trivial to run commands that don't show up in the history). See How can I log all process launches in Linux.

If you're debugging a script then shell history is not the best way to get useful information. A much better tool is the debug trace facility: put set -x near the top of the script. The trace is written to standard error.

Best Answer

Related Solutions

bash – Preserve Bash History in Multiple Terminal Windows

Bash – History command inside bash script

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