I'm trying to update the previous command prompt with the time when the command was written.
With the code I wrote, typing the following command
[--:--] costam:~ $ echo "Wrote this at 10:20"
and launching it after five minutes, results in this output:
[10:25] costam:~ $ echo "Wrote this at 10:20"
Wrote this at 10:20
The code in the zsh-theme to achieve this, is the following
PROMPT='[--:--] %{$fg[red]%}$USER:%{$reset_color%}%{$fg[green]%}%c%{$reset_color%}$(git_prompt_info) %(!.#.$) '
preexec () {
DATE=`date +"%H:%M"`
echo -e "\r\033[1A[${DATE}]"
}
The problem is when the command exceed one line or there's an activated virtual env. In such cases, the prompt is not overridden where it should, and results in this:
# Multiline
[--:--] costam:~ (master) $ cat ~/.oh-my-zsh/custom/themes/davever
[10:20]-theme
# Virtualenv
[10:20]env) [--:--] costam:~ (master) $ echo "Broken"
Broken
A solution I was thinking of, was of finding the current prompt in preexec() and then replace [--:--] with the current time, but I don't know how or if is even possible to get the current prompt.
Any other solution is welcome, as long as the time is printed in the same way (or very similar) and not, for example, printing on the right side using RPROMT or printing in the new prompt.
Thank you!
You can just use %T to get the current time in your prompt sequence.
Additionally, rather than put raw escape codes in your prompt, you can simplify your prompt string by using %F{<color>} and %f instead.
So, remove that preexec function and use this as your prompt:
PROMPT='[%T] %F{red}$USER:%F{green}%c%f$(git_prompt_info) %(!.#.$) '
What if you asked ZSH to refresh the terminal prompt with the current time periodically?:
PROMPT='[%D{%L:%M}] %{$fg[red]%}$USER:%{$reset_color%}%{$fg[green]%}%c%{$reset_color%}$(git_prompt_info) %(!.#.$) '
TMOUT=1
TRAPALRM() {
zle reset-prompt
}
Sample output which tracks the current time on the computer, down to the second:
[11:41] costam:~ $
%D{%L:%M} will have the same effect as your use of date +"%H:%M". TMOUT suggestion found here. Since you only want the hour and minute, you might be able to increase the TMOUT value to 10 seconds or more.
Related
TLDR;
I need a way for .zshrc to automatically be sourced each time a command is executed. PROMPT needs to be updated each time a command is executed in order to show relevant information in the prompt.
Reason
I use Watson cli for tracking time. On my previous bash setup, I prepended my prompt ($PS1) with a symbol that indicates whether the timer is running or not (red/green). I have mimicked this functionality with Oh My Zsh, as follows (in the theme file):
WATSON_DIR="$HOME/Library/Application Support/watson"
watson_status() {
local txtred="${fg_bold[red]}"
local txtgrn="${fg_bold[green]}"
local txtrst="${reset_color}"
# Started
local status_color="$txtgrn"
# Stopped
if [[ $(cat "$WATSON_DIR/state") == '{}' ]]; then
status_color="$txtred"
fi
echo -e "$status_color""◉""$txtrst"
}
PROMPT="╭── %{$(watson_status) $fg_bold[green]%}%~%{$reset_color%}$(git_prompt_info) ⌚ %{$FG[130]%}%*%{$reset_color%}
╰─➤ $ "
Current issue
The icon will indicate the color of the state at the time that .zshrc was executed. For example, if the timer is running and the icon is properly indicating green, stopping the timer will not cause the icon to turn red. In order to see the icon change color, I have to source .zshrc.
This indicates that the function watson_status() needs to be run each time a command is executed, to give the latest status at the time of the command
I recently ported some prompt code from bash to zsh - on OSX Big Sur - and these were the two big "things to know" for me:
add setopt PROMPT_SUBST to your .zshrc. This "allows for functions in the prompt"
use single quotes when defining your PS1 / PROMPT. If you use double quotes, then the whole string will be evaluated once when the terminal starts, and then that evaluated value is "re-executed" every time the command changes. But you want the functions to be re-evaluated, not the output of the function at the time when the terminal is created.
Easiest example I used to confirm I had it working:
# print_epoch() { date '+%s' }
# this is what you want
# export PS1='$(print_epoch) > '
# this is not what you want
# export PS1="$(print_epoch) > "
Also worth noting PS1 and PROMPT are interchangeable
Extra:
While we are sharing here is my fairly minimal echo my user, directory, and git branch PROMPT with some colors and a pretty leaf:
parse_git_branch() {
git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/\1/'
}
setopt PROMPT_SUBST
autoload -U colors && colors
export PROMPT='%n %~ %F{blue}🌿$(parse_git_branch)%f > '
noting that:
%n prints name
%~ prints directory relative to home
%F{blue} changes text to blue
%f resets color
Documentation: http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html#Visual-effects
my zsh shell has a quite long start up time and if I hold done the enter key the terminal prompt lags behind significantly. So I looked out for solutions and profiling options and found this github issue. Further done one comment suggests to run the following commands:
zsh -xv 2>&1 | ts -i "%.s" > zsh_startup.log
followed by
sort --field-separator=' ' -r -k1 zsh_startup.log> sorted.log
which gives me the following output:
2.106722 ESC[?1hESC=ESC[?1lESC>l
1.388755 ESC[?1hESC=ESC[?1lESC>l
1.185498 ESC[?1hESC=ESC[?1lESC>exit
1.153527 ESC[?1hESC=ESC[?1lESC>ls -la
0.065941 +powerline_precmd:1> PS1=$'%{\C-[[38;5;15m%}%{\C-[[48;5;31m%} ~ %{\C-[[48;5;237m%}%{\C-[[38;5;31m%}%{\C-[[38;5;250m%}%{\C-[[48;5;237m%} Private %{\C-[[48;5;237m%}%{\C-[[38;5;244m%}%{\C-[[38;5;254m%}%{\C-[[48;5;237m%} tmp %{\C-[[48;5;238m%}%{\C-[[38;5;237m%}%{\C-[[38;5;39m%}%{\C-[[48;5;238m%} 1 %{\C-[[48;5;236m%}%{\C-[[38;5;238m%}%{\C-[[38;5;15m%}%{\C-[[48;5;236m%} %# %{\C-[[0m%}%{\C-[[38;5;236m%}%{\C-[[0m%} '
0.052396 +powerline_precmd:1> PS1=$'%{\C-[[38;5;15m%}%{\C-[[48;5;31m%} ~ %{\C-[[48;5;237m%}%{\C-[[38;5;31m%}%{\C-[[38;5;250m%}%{\C-[[48;5;237m%} Private %{\C-[[48;5;237m%}%{\C-[[38;5;244m%}%{\C-[[38;5;254m%}%{\C-[[48;5;237m%} tmp %{\C-[[48;5;238m%}%{\C-[[38;5;237m%}%{\C-[[38;5;39m%}%{\C-[[48;5;238m%} 1 %{\C-[[48;5;236m%}%{\C-[[38;5;238m%}%{\C-[[38;5;15m%}%{\C-[[48;5;236m%} %# %{\C-[[0m%}%{\C-[[38;5;236m%}%{\C-[[0m%} '
...
It looks like the first four commands (or whatever the lines represent) are taking up the majority of the time. I'm having a hard time understanding the output and would like to have some guidance in interpreting the first lines - no need for solving the underlying problem of having a slow shell :) just the interpretation of the first four lines.
The file itself is much longer and I just included the first few lines.
Notes:
I'm using oh-my-zsh with the following plugins
plugins=(
z
git
kubectl
zsh-syntax-highlighting
zsh-autosuggestions
)
I configured l to be an alias for l -la in my .zshrc
this is what happens when I keep pressing the enter key:
(when there are no gaps between prompts I had already released the enter key again)
For example,
I executed "pwd" and it shows the current working directory. Then if I want to reuse that result in my another command, it would convenient to get it via a Unix command or built-in variable. Does it exist?
You can get the result, as in return code, using $?. In order to get the output you'll need to explicitly keep it around - e.g. with:
MYVAR=`pwd`
echo $MYVAR
Use $? inorder to get the status of the last executed command. Its value will be zero if the last executed command was successful else non zero.
The internal variable $? holds the return value of the last executed command or program. Example: http://tldp.org/LDP/abs/html/complexfunct.html#MAX.
If you don't need to run one command first, you can also try using pipes | to connect commands. I am constantly piping long directory listings over to more, so I can page through the results, with
ls -al | more
so if you want to use the results of running pwd as input to another program, you can try something like piping the results of pwd over to more with
pwd|more
I know that I can exec a date command in my zsh prompt.
However, it shows the old time; to see the current time, I have to hit <return> and get a new prompt with the current time.
Is there a way to configure the zsh prompt to constantly update itself every second?
Note: I wrote this answer for a similar question, but seeing how this question has more views I think reposting my answer here would be useful.
This is in fact possible without resorting to strange hacks. I've got this in my .zshrc
RPROMPT='[%D{%L:%M:%S %p}]'
TMOUT=1
TRAPALRM() {
zle reset-prompt
}
The TRAPALRM function gets called every TMOUT seconds (in this case 1), and here it performs a prompt refresh, and does so until a command starts execution (and it doesn't interfere with anything you type on the prompt before hitting enter).
Source: http://www.zsh.org/mla/users/2007/msg00944.html (It's from 2007!)
Sounds like a pleasant request to me. If anything it makes more sense than showing the time when the prompt was displayed.
Fortunately Peter Stephenson posted a technique. Try something like this in .zshrc:
PROMPT="[%T] %n#%M %~ %# "
schedprompt() {
emulate -L zsh
zmodload -i zsh/sched
# Remove existing event, so that multiple calls to
# "schedprompt" work OK. (You could put one in precmd to push
# the timer 30 seconds into the future, for example.)
integer i=${"${(#)zsh_scheduled_events#*:*:}"[(I)schedprompt]}
(( i )) && sched -$i
# Test that zle is running before calling the widget (recommended
# to avoid error messages).
# Otherwise it updates on entry to zle, so there's no loss.
zle && zle reset-prompt
# This ensures we're not too far off the start of the minute
sched +30 schedprompt
}
schedprompt
This would be .... unpleasant in a standard zsh prompt (or bash, or other shells).
I suggest you'd be better off using Gnu Screen.
Screen can have a status line which can show the time.
Here's an example screenrc scroll down to "Red Hat Magazine A guide to GNU Screen" to see the sample (i'll reproduce that here) which will, when screen is run, show the current time in the lower right corner of the terminal:
~/.screenrc
hardstatus alwayslastline
hardstatus string '%{= kG}[ %{G}%H %{g}][%= %{=kw}%?%-Lw%?%{r}(%{W}%n*%f%t%?(%u)%?%{r})%{w}%?%+Lw%?%?%= %{g}][%{B}%Y-%m-%d %{W}%c %{g}]'
# Default screens
screen -t shell1 0
screen -t shell2 1
http://www.gnu.org/software/screen/
What is the meaning for $! in shell or shell scripting? I am trying to understand a script which has the something like the following.
local#usr> a=1
local#usr> echo $a
1
local#usr> echo $!a
a
It is printing the variable back. Is it all for that? What are the other $x options we have? Few I know are $$, $*, $?. If anyone can point me to a good source, it will be helpful. BTW, This is in Sun OS 5.8, KSH.
The various $… variables are described in Bash manual. According to the manual $! expands to the PID of the last process launched in background. See:
$ echo "Foo"
Foo
$ echo $!
$ true&
[1] 67064
$ echo $!
67064
[1]+ Done true
In ksh it seems to do the same.
From the ksh man page on my system:
${!vname}
Expands to the name of the variable referred to by vname. This
will be vname except when vname is a name reference.
For the shell you are asking, ksh, use the the ksh manual, and read this:
Parameter Substitution
A parameter is an identifier, one or more digits, or any of
the characters *, #, #, ?, -, $, and !.
It is clear that those are the accepted options $*, $#, $#, $?, $-, $$, and $!.
More could be included in the future.
For the parameter $!, from the manual:
"!" The process number of the last background command invoked.
if you start a background process, like sleep 60 &, then there will be a process number for such process, and the parameter $! will print its number.
$ sleep 60 &
[1] 12329
$ echo "$!"
12329
If there is no background process in execution (as when the shell starts), the exansion is empty. It has a null value.
$ ksh -c 'echo $!'
If there is a background process, it will expand to the PID of such process:
$ ksh -c 'sleep 30 & echo $!'
42586
That is why echo $!a expanded to a. It is because there is no PID to report:
$ ksh -c 'echo $!a'
a
Other shells may have a different (usually pretty similar) list of expansions (a parameter with only one $ and one next character).
For example, bash recognize this *##?-$!0_ as "Special parameters". Search the Bash manual for the heading "3.4.2 Special Parameters".
Special Parameters
The shell treats several parameters specially.
It gives the Process id of last backgroundjob or background function
Please go through this link below
http://www.well.ox.ac.uk/~johnb/comp/unix/ksh.html#specvar
! is a reference operator in unix, though it is not called with that name.
It always refers to a mother process. Try typing :! in vi, it takes you to command prompt and you can execute commands as usual until exit command.
! in SQLPLUS also executes the command from the command prompt. try this in sqlplus
SQL> !ls --- this gives the list of files inthe current dir.
$! - obviously gives the process id of the current/latest process.