CODEWITHSUNDEEP
bash
Krackout
Krackout

Reputation: 282

Pass every command executed in the bash shell to a variable

I'd like to pass every command executed in the bash shell to a variable, in order to be used to change a label showing running app.

Since newer versions of bash have preexec hook, PS0 (expanded and displayed after reading a command and before the command is executed) and PROMPT_COMMAND (value is interpreted as a command to execute before the printing of each primary prompt), I'm thinking of using these to achieve the change of label.
PS0 as shown below and PROMPT_COMMAND="printf '\033kBASH\033\\'" so that label is restored to BASH after the typed command is executed.

So for example, top is started,

$ top Enter

Ideally top, as a string, would be assigned to $TO_BE_EXECUTED_APP var which would be used to something like
PS0="print '\033k$TO_BE_EXECUTED_APP\033\\'"

These escape sequences can be used by tmux for example to change its window label.

What I can't achieve is to populate the $TO_BE_EXECUTED_APP with the to-be-executed command as a string.

I tried using $BASH_COMMAND, no positive result.

Using this shell function I can manually achieve what a I need:

exelabel() {
        printf "\033k$@\033\\"
        "$@"

$ exelabel top Enter

But of course I'd like this to be done automatically. Any ideas?

Upvotes: 0

Views: 345

Answers (2)

Philippe
Philippe

Reputation: 26592

You can use this to get current command :

HISTTIMEFORMAT= history 1 | sed -e "s/^[ ]*[0-9]*[ ]*//"

This is what I use to display current command on xterm title :

PS0='$(printf "\e]0;%s\7" "$(HISTTIMEFORMAT= history 1 | sed -e "s/^[ ]*[0-9]*[ ]*//")")'

In your case, you can do (update after comments):

PS0='$(printf "\033k%s\033" "$(HISTTIMEFORMAT= history 1 | sed -e "s/^[ ]*[0-9]*[ ]*//")")'

or

PS0='$(printf "\033k%s\033\\\\" "$(HISTTIMEFORMAT= history 1 | sed -e "s/^[ ]*[0-9]*[ ]*//")")'

Upvotes: 1

Krackout
Krackout

Reputation: 282

@Philippe:

Entering

PS0='$(printf "\033k%s\033\\" "$(HISTTIMEFORMAT= history 1 | sed -e "s/^[ ]*[0-9]*[ ]*//")")'

produces these errors after each Enter

bash: command substitution: line 32: unexpected EOF while looking for matching `"'
bash: command substitution: line 33: syntax error: unexpected end of file
bash: command substitution: line 1: unexpected EOF while looking for matching `"'
bash: command substitution: line 2: syntax error: unexpected end of file

I also assigned the same line to a test variable:

testing='$(printf "\033k%s\033\\" "$(HISTTIMEFORMAT= history 1 | sed -e "s/^[ ]*[0-9]*[ ]*//")")'

If I type at prompt:
$ $testing Enter

I get this error:

bash: $(printf: command not found

Also tried to remove space after printf, the error changes to:

bash: $(printf"\033k%s\033\\": command not found

Upvotes: 0

Related Questions