Tcsh completion in the format of ls -l - linux

When setting autolist in tcsh.rc, and pressing Tab to complete a filename i get a list of available completions in the format of a "regular" ls command.
is there any way to set tcsh in a way that pressing tab will show a list of available completions in the format of "ls -l"?
or if not, then just sort the "regular" list by date?

pressing tab will show a list of available completions in the format of "ls -l"?
No, this is not possible.
Completion in tcsh works by getting a list of words (ie. my trousers are on fire), checking if one of the word matches, and then insert that word in the commandline.
There is no functionality which says "display this to the user, but insert something else in the commandline". So while you could complete commands with ls -l, this would be fairly useless, since you'll get the entire line in your commandline.
just sort the "regular" list by date?
This is also not possible, since tcsh sorts the completions. You can't disable this ...
Sorry :-( I believe that at least zsh is able to do this, but I'm not sure. Maybe bash can do this as well (but again, not sure).
(This information derived from a careful reading of the manpage, and tw.parse.c in the source code.)

Related

tmux pin to avoid scrolling

Often when I run a command that writes to stdout, and that command fails, I have to scroll up (using uncomfortable key-bindings) looking for the place where I pressed Enter, to see what the first error was (out of hundreds others, across many screens of text). This is both annoying and time-consuming. I wish there was a feature which allowed me to pin my current terminal to the place where I am now, then start the command, see only the first lines of the output (as many as fits below my cursor) and let the rest of the output be written but not displayed. In other words I would like a feature to allow me automatically scroll up to the place where I gave the command, to see the first lines of the output (where usually the origin of the failure is displayed).
I searched for it but I didn't find it. Do you know if such feature exists? Or have an idea how to implement it with some tricks or workarounds?
If you have a unique shell prompt you could bind a key to jump between shell prompts, for example something like this will make C-b S jump to the previous shell prompt then S subsequent ones:
bind S copy-mode \; send -X search-backward 'nicholas#myhost:'
bind -Tcopy-mode S send -X search-backward 'nicholas#myhost:'
Or similarly you could search for error strings if they have a recognisable prefix. If you install the tmux 3.1 release candidate, you can search for regular expressions.
Alternatively, you could use capture-pane to load the entire history into an editor with key bindings you prefer, for example:
$ tmux capturep -S- -E- -p|vim -
Or pipe to grep or whatever. Note you will need to use a temporary file for this to work with emacs.
Or try to get into the habit of teeing commands with lots of output to a file to start with.

How can I use vim in a pipeline to colorize text?

I'd like to have a command I can insert into a command pipeline that adds color escapes to its input according to vim's syntax highlighting capabilities.
For example:
cat somefile.js | vim - <???> | less
The resulting text would be that of somefile.js, but colorized according to how the current vim configuration would do it in-editor.
It occurs to me that this must be possible. I agree that the example up there isn't what a sane man might call exactly useful, but that doesn't mean the idea never is.
I think your idea has one basic flaw: that nobody ever thought about allowing such a thing.
Clearly vim is capable of doing syntax highlighting. But I'll bet you an ice cream cone that if you can manage to get vim to stream text through and process it, that you won't like the results.
Consider what happens when you pipe text through more (or less if you prefer). When it goes to the terminal, these programs display one screenful and wait for you to hit the space bar. But if you redirect stdout to some other place than the terminal, these programs notice this and simply copy their input to their output unchanged.
If vim doesn't notice that you are piping text through, it is likely to send cursor-movement commands that you probably don't want in your output. If vim does notice, it is likely to just pass the text, and not syntax-color it. Only if vim does do the syntax-coloring but does not inject cursor-movement stuff will your idea work.
You could try it. Here's an answer that discusses piping stuff through vim:
Execute a command within Vim from the command line
But I say why not pipe your text through a program that was designed and intended to have text piped through it? Pygments can colorize every major programming language and markup format.
http://pygments.org/
The major advantage I see for your idea: you can customize the way vim does syntax coloring, get it the way you want it, and then also use vim to process your text. But it's probably not that hard to customize Pygments, and it might even be satisfactory out of the box, in which case it would definitely be the easiest way to go. And Pygments not only has ANSI sequence output, it also has HTML output, RTF, LaTeX, etc. So if you get Pygments working the way you want it to, it should be able to output whatever output format you need; vim will only have the ANSI sequence one.
There's a Perl module called Text::VimColor that I've heard will do kinda what you're looking for.
http://search.cpan.org/dist/Text-VimColor/
But let me ask this: Why do want it to go through less? Why not use vim as a perfectly good file viewer? view - will read from standard input in read-only mode.
https://gist.github.com/echristopherson/4090959
Via https://superuser.com/a/554531/7198.
Tried on /etc/passwd and it works surprisingly well!
This might be what you're after
cat filename.sh | vim - -c 'syntax on; syn=bash'
This is ugly, but you could alias this:
alias vim.sh="vim -c 'syntax on; syn=bash'"
Then use like this:
cat filename.sh | vim.sh -
Use vimcat !
wget -O /usr/local/bin/vimcat "https://www.vim.org/scripts/download_script.php?src_id=23422"
chmod 755 /usr/local/bin/vimcat
vimcat /etc/passwd
See also: https://www.vim.org/scripts/script.php?script_id=4325

Use Vim to "colourize" files or input streams

This may be an odd question, but still. I use cat to display a file in bash (KDE Konsole),
cat foobar.rb
Now, I would like to use Vim to colourize that foobar.rb file according to what you would get when you start foobar.rb in Vim. Edit: But only for display purpose, on the terminal.
I am not sure this is possible, but I thought it would be neat if I could use Vim for that.
I really just want colourized keywords, and Vim has the perfect colour definitions.
So I thought combining this would be great.
Is this possible in Vim out of the box though?
One approach would be to use a library such as Pygments, which is a general purpose syntax highlighter. You could write a wrapper called ccat or something that would apply syntax highlighting to an input file and write to stdout.
If you want to page up and down in a highlighted file, you can use less with the -R switch, which passes control characters through to the terminal directly, preserving colours. So:
ccat file.rb | less -R
But at that point, you're pretty much at the capabilities of view.
I'm not sure if I understand your question correctly, but if you are only looking for a command that will give you a read-only view of the input file (like cat) but with coloured keywords, use view. view is an alternative way to start vim in read-only mode, so you have all syntax highlighting possibilities. From the vim man page:
view Start in read-only mode. You will be protected from writing
the files. Can also be done with the "-R" argument.
gvim gview
The GUI version. Starts a new window. Can also be done with
the "-g" argument.
evim eview
The GUI version in easy mode. Starts a new window. Can also
be done with the "-y" argument.
rvim rview rgvim rgview
Like the above, but with restrictions. It will not be possi-
ble to start shell commands, or suspend Vim. Can also be
done with the "-Z" argument.
I have always seen view on systems that have vim installed.
Closest is the less script that comes with vim:
cat myfile | vim -u /usr/share/vim/vim72/macros/less.vim -
Note the - argument to vim. You may need to change the vim72 to your version (and the whole path if you have it installed elsewhere)
Now, this isn't exactly what you want, because its behaviour is less-like, in that you have to press keys to make it scroll down or complete. However, they are briefer than usual vim. For example, space to scroll down; and q to quit (not :q).
You want a cat-like version; me too. But there doesn't seem to be one.
EDIT uh, there's also a vimpager project, that includes vimcat - exactly what you want. But it doesn't come with vim, and I haven't tried it yet.
vim.org: http://www.vim.org/scripts/script.php?script_id=1723
github: https://github.com/rkitover/vimpager

Dynamic abbrev expand for the shell

Is there a function on one of the linux shells like the emacs dabbrev-expand?
First to give a definition:
M-xdescribe-functionEnterdabbrev-expandEnter
...
Expands to the most recent, preceding word for which this is a prefix.
Given that bash seems to be most heavily influenced by Emacs, looking there first reveals a few possibilities:
man bash(1), readline section
dynamic-complete-history (M-TAB)
Attempt completion on the text before point, comparing the text
against lines from the history list for possible completion matches.
dabbrev-expand
Attempt menu completion on the text before point, comparing the text
against lines from the history list for possible completion matches.
By default (or my system at least), M-/ is already bound to complete-filename:
$ bind -l | grep /
"\e/": complete-filename
You could re-bind it by putting
"\e/": dabbrev-expand
in your ~/.inputrc or /etc/inputrc.
Note that it only seems to complete the first word (the command), and only from history, not from the current command line as far as I can tell.
In zsh, I can't see anything in the man page that does this, but it should be possible to make it happen by figuring out the appropriate compctl command (Google mirror).

How can I view log files in Linux and apply custom filters while viewing?

I need to read through some gigantic log files on a Linux system. There's a lot of clutter in the logs. At the moment I'm doing something like this:
cat logfile.txt | grep -v "IgnoreThis\|IgnoreThat" | less
But it's cumbersome -- every time I want to add another filter, I need to quit less and edit the command line. Some of the filters are relatively complicated and may be multi-line.
I'd like some way to apply filters as I am reading through the log, and a way to save these filters somewhere.
Is there a tool that can do this for me? I can't install new software so hopefully it's something that would already be installed -- e.g., less, vi, something in a Python or Perl lib, etc.
Changing the code that generates the log to generate less is not an option.
Use &pattern command within less.
From the man page for less
&pattern
Display only lines which match the pattern; lines which do not
match the pattern are not displayed. If pattern is empty (if
you type & immediately followed by ENTER), any filtering is
turned off, and all lines are displayed. While filtering is in
effect, an ampersand is displayed at the beginning of the
prompt, as a reminder that some lines in the file may be hidden.
Certain characters are special as in the / command:
^N or !
Display only lines which do NOT match the pattern.
^R Don't interpret regular expression metacharacters; that
is, do a simple textual comparison.
Try the multitail tool - as well as letting you view multile logs at once, I'm pretty sure it lets you apply regex filters interactively.
Based on ghostdog74's answer and the less manpage, I came up with this:
~/.bashrc:
export LESSOPEN='|~/less-filter.sh %s'
export LESS=-R # to allow ANSI colors
~/less-filter.sh:
#!/bin/sh
case "$1" in
*logfile*.log*) ~/less-filter.sed < $1
;;
esac
~/less-filter.sed:
/deleteLinesLikeThis/d # to filter out lines
s/this/that/ # to change text on lines (useful to colorize using ANSI escapes)
Then:
less logfileFooBar.log.1 -- applies the filter applies automatically.
cat logfileFooBar.log.1 | less -- to see the log without filtering
This is adequate for now but I would still like to be able to edit the filters on the fly.
see the man page of less. there are some options you can use to search for words for example. It has line editing mode as well.
There's an application by Casstor Software Solutions called LogFilter (www.casstor.com) that can edit Windows/Mac/Linux text files and can easily perform file filtering. It supports multiple filters as well as regular expressions. I think it might be what you're looking for.

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