I have a custom prompt in Zsh. At the end of it, I colour the last character red or green depending on if the last command succeeded or failed. However, when I do this, I can't go back and edit previous commands.
This is the prompt code:
%{%F%(?.$fg[green].$fg[red])>%f%}
An example workflow:
I enter a command that wraps onto a new line:
> printf "%s\n" "This is a very long printf. How long is it? It's so very very long that it wraps onto the next line."
After this runs, I hit up arrow and modify the command by deleting and retyping "is it". Now, the command line shows:
> printf "%s\n" "This is a very long printf. How long is it It's so very very long that it wraps onto the next line."
This prints out:
This is a very long printf. How long iis it It's so very very long that it wraps onto the next line.
I assume that I'm not terminating the color codes somehow so that the prompt is spilling over into the actual commands I'm trying to enter. It only misbehaves when the prompt wraps around to a new line. Can anyone see what's wrong with my prompt?
I've verified that, without this snippet of code, the rest of the prompt is fine and behaves as you'd expect.
zsh is confused about how long the prompt actually is. The shell already knows that its own %F escape doesn't contribute to the on-screen length of the prompt; you don't need to wrap it in %{...%} like you would similarly do in bash.
PS1="%F%(?.$fg[green].$fg[red])>%f"
If fg contains actual terminal-specific escape sequences, then you would need %{...%}, but you wouldn't use %F at all, as this isn't how you use it. So you might actually need something like
PS1="%(?.%{$fg[green]%}.%{$fg[red]}%})>%f"
But, you don't need a separate array of colors; zsh has them built in as well.
PS1='%(?.%F{green}.%F{red})>%f '
Related
Can I use zsh vi normal mode to move around previous commands output or the printed text in the shell to copy/yank it ?
For example in the screenshot below. I want to move to the output of ls to copy something. When I press j/k zsh cycle my command history but doesn't move up to the printed text. j/k move one line down/up only when I have multiple line command that I'm currently writing but haven't executed yet.
To the best of my knowledge, the ability to access the output of commands interactively is the domain of your terminal (-emulator), not the shell. You would use commands like sed, awk, grep, possibly in a pipe, to access, manipulate and use output you know in advance is the part you are interested in.
To access the output with keyboard shortcuts/command-keys, I suggest using the like of tmux - it allows to copy/yank from the whole terminal display as if it was a text-file in an editor.
I'm trying to figure out how to get file completion to work at any word position on the command line after a set of characters. As listed in a shell these characters would be [ =+-\'\"()] (the whitespace is tab and space). Zsh will do this, but only after the backtick character, '`', or $(. mksh does this except not after the characters [+-].
By word position on the command line, I'm talking about each set of characters you type out which are delimited by space and a few other characters. For example,
print Hello World,
has three words at positions 1-3. At position 1, when you're first typing stuff in, completion is pretty much perfect. File completion works after all of the characters I mentioned. After the first word, the completion system gets more limited since it's smart. This is useful for commands, but limiting where you can do file completion isn't particularly helpful.
Here are some examples of where file completion doesn't work for me but should in my opinion:
: ${a:=/...}
echo "${a:-/...}"
make LDFLAGS+='-nostdlib /.../crt1.o /.../crti.o ...'
env a=/... b=/... ...
I've looked at rebinding '^I' (tab) with the handful of different completion widgets Zsh comes with and changing my zstyle ':completion:*' lines. Nothing has worked so far to change this default Zsh behaviour. I'm thinking I need to create a completion function that I can add to the end of my zstyle ':completion:*' completer ... line as a last resort completion.
In the completion function, one route would be to cut out the current word I want to complete, complete it, and then re-insert the completion back into the line if that's possible. It could also be more like _precommand which shifts the second word to the first word so that normal command completion works.
I was able to modify _precommand so that you can complete commands at any word position. This is the new file, I named it _commando and added its directory to my fpath:
#compdef -
# precommands is made local in _main_complete
precommands+=($words[1,$(( CURRENT -1 ))])
shift words
CURRENT=1
_normal
To use it I added it to the end of my ':completion:*' completer ... line in my zshrc so it works with every program in $path. Basically whatever word you're typing in is considered the first word, so command completion works at every word position on the command line.
I'm trying to figure out a way to do the same thing for file completion, but it looks a little more complicated at first glace. I'm not really sure where to go with this, so I'm looking to get some help on this.
I took a closer look at some of Zsh's builtin functions and noticed a few that have special completion behaviour. They belong to the typeset group, which has a function _typeset in the default fpath. I only needed to extract a few lines for what I wanted to do. These are the lines I extracted:
...
elif [[ "$PREFIX" = *\=* ]]; then
compstate[parameter]="${PREFIX%%\=*}"
compset -P 1 '*='
_value
...
These few lines allow typeset completion after each slash in a command like this:
typeset file1=/... file2=~/... file3=/...
I extrapolated from this to create the following function. You can modify it to put in your fpath. I just defined it in my zshrc like this:
_reallyforcefilecompletion() {
local prefix_char
for prefix_char in ' ' $'\t' '=' '+' '-' "'" '"' ')' ':'; do
if [[ "$PREFIX" = *${prefix_char}* ]]; then
if [[ "$PREFIX" = *[\'\"]* ]]; then
compset -q -P "*${prefix_char}"
else
compset -P "*${prefix_char}"
fi
_value
break
fi
done
}
You can use this by adding it to a zstyle line like this:
zstyle ':completion:*' completer _complete _reallyforcefilecompletion
This way, it's only used as a last resort so that smarter completions can try before it. Here's a little explanation of the function starting with the few variables and the command involved:
prefix_char: This gets set to each prefix character we want to complete after. For example, env a=123 has the prefix character =.
PREFIX: Initially this will be set to the part of the current word from the beginning of the word up to the position of the cursor; it may be altered to give a common prefix for all matches.
IPREFIX (not shown in code): compset moves string matches from PREFIX to IPREFIX so that the rest of PREFIX can be completed.
compset: This command simplifies modification of the special parameters, while its return status allows tests on them to be carried out.
_value: Not really sure about this one. The documentation states it plays some sort of role in completion.
Documentation for the completion system
The function: In the second line, we declare prefix_char local to avoid variable pollution. In line three, we start a for loop selecting each prefix_char we want to complete after. In the next if block, we check if the variable PREFIX ends with one of the prefix_chars we want to complete after and if PREFIX contains any quotes. Since PREFIX contains quotes, we use compset -q to basically allow quotes to be ignored so we can complete in them. compset -P strips PREFIX and moves it to IPREFIX, basically so it gets ignored and completion can work.
The next elif statement is for a PREFIX ending with prefix_char but not containing quotes, so we only use compset -P. I added the return 0 to break the loop. A more correct way to make this function would be in a case statement, but we're not using the compset return value, so this works. You don't see anything about file completion besides _value. For the most part we just told the system to ignore part of the word.
Basically this is what the function does. We have a line that looks like:
env TERM=linux PATH=/<---cursor here
The cursor is at the end of that slash. This function allows PREFIX, which is PATH=, to be ignored, so we have:
env TERM=linux /<---cursor here
You can complete a file there with PATH= removed. The function doesn't actually remove the PATH= though, it just recategorizes it as something to ignore.
With this function, you can now complete in all of the examples I listed in the question and a lot more.
One last thing to mention, adding this force-list line in your zshrc cripples this function somehow. It still works but seems to choke. This new force-list function is way better anyway.
zstyle ':completion:*' force-list always
EDIT: There were a couple lines I forgot to copy into the function. Probably should have checked before posting. I think it's good now.
This question is about configuring the R console to behave like a bash shell when it comes to navigating the command history. It is somewhat related to the ?history. For brace-enclosed multi-lines, I'd like to configure the command history navigation of R to be similar to bash.
Presently when running R in an xterm under Linux, using the up-arrow to navigate the command history causes each previous line to be recalled one by one, even if a set of lines had been enclosed in braces. This occurs, for example, when copy/pasting a multi-line function from a text editor into the R console. Not so with bash.
Here is an example of how bash functions in this regard:
In a bash shell within an xterm under Linux, after typing the following five lines...
a=1
{
x=1
y=1
}
... the first press of the up-arrow will recall a single line reformulation of the brace-enclosed commands, like this ...
{ x=1; y=1; }
... and the second press will recall this ...
a=1
It seems that in R, the up-arrow navigates backwards one line at a time, regardless of encapsulation. Is there a way to configure R so that it's command history navigation functions like bash's?
You could use rlwrap. I use it for other console programs and it works very well. You will need to prepend the R command with the rlwrap binary and then your history lines can be restored in a number of ways, including multi-line matching.
Workaround for Linux/Unix
Similarly as in Rstudio (thanks to Ari B. Friedman comment), where user in R console is using ShiftEnter to bypass RETURN, you can start newline (in R terminal) without accepting newline command using Ctrl-VCtrl-J. This way the multi-line command will be accepted into history as one-liner with line-feeds instead of enters and you will even have the chance to edit it. You can even manage in your .inputrc file to have custom combination for this action.
I do not think direct reconfiguration of R is possible.
Readline man page may help more.
I'm writing a program (in python) that calls a separate program (via subprocess). I'm finding that in some cases the sub program is getting stuck running. I can see the sub-program by running top, and if i press "c", I can see the full command line.
What I want, is to be able to stick debugging data (like current thread id, etc) in the command line when i'm calling the sub program, so I can futher debug my problem.
Is there a way to put comments in command line arguments such that they show up in top?
I can't think of a direct way but you could write a little shell script to which you pass the actual command to run plus argument and debugging information. It would show up in the top/ps output.
Instead of making them comments, put them in the environment. For example, if you have a /proc file system, you could do:
FOO=value cmd
When top shows the pid of the command, do:
tr '\000' '\012' < /proc/pid/environ | grep FOO
to see the value of FOO in the environment of the cmd. If the values contain newlines, you will need to be more careful about the display, something like:
perl -n0E 'say if /FOO/' /proc/pid/environ
#!/bin/bash
echo 'first line' >foo.xml
echo 'second line' >>foo.xml
I am a total newbie to shell scripting.
I am trying to run the above script in cygwin. I want to be able to write one line after the other to a new file.
However, when I execute the above script, I see the follwoing contents in foo.xml:
second line
The second time I run the script, I see in foo.xml:
second line
second line
and so on.
Also, I see the following error displayed at the command prompt after running the script:
: No such file or directory.xml
I will eventually be running this script on a unix box, I am just trying to develop it using cygwin. So I would appreciate it if you could point out if it is a cygwin oddity and if so, should I avoid trying to use cygwin for development of such scripts?
Thanks in advance.
Run dos2unix on your shell script. That will fix the problem.
I had the same kind of problem as the original poster: A very simple script file was not working in Cygwin.
Thanks to Don Branson for the clue.
The fix for me was built into the text editor I'm using. (Most programmer's editors have a feature like this.) For example, in my case I'm using Notepad++, which has a menu item to convert the file line endings to Unix-style. From the menu: [Edit]->[EOL Conversion]->[Unix (LF)]
Then the script behaved as expected.
But there must be something else that is wrong here. When I try it, it works as expected.
> foo.xml puts the line into foo.xml, replacing any previous contents.
>> foo.xml appends to file
It sounds like you may have a typo somewhere. Also keep in mind that while the Windows command prompt can be forgiving about paths with embedded spaces, cygwin's shells will not be, so if you have a filename that contains embedded spaces, you need to either quote the filename or escape the spaces:
echo 'first line' > 'My File.txt'
echo 'first line' > My\ File.txt
The same goes for certain "special" characters including quotes, ampersand (&), semicolons (;) and generally most punctuation other than period/full-stop (.).
So if you are seeing those issues using the exact script that you are running (i.e. you copy and pasted it, there is no possibility of transcription errors) then something truly strange may be happening that I can't explain. Otherwise, there may be a misplaced space or unquoted character somewhere.
I cannot reproduce your results. The script you quote looks correct, and indeed works as expected in my installation of Cygwin here, producing the file foo.xml containing the lines first line and second line; implying that what you are actually running differs from what you quoted in some way that is causing the problem.
The error message implies some sort of problem with the filename in the first echo line. Do you have some nonprintable characters in the script you are running? Have you missed escaping a space in the filename? Are you subsituting shell variables and mistyping the name of the variable or failing to escape the resulting string?
The above should work normally..
However you can always specify a heredoc:
#!/bin/bash
cat <<EOF > foo.xml
first line
second line
EOF