I am attempting to bend zsh, my shell of choice, to my will, and am completely at a loss on the syntax and operation of completions.
My use case is this: I wish to have completions for 'ansible-playbook' under the '-e' option support three variations:
Normal file completion: ansible-playbook -e vars/file_name.yml
Prepended file completion: ansible-playbook -e #vars/file_name.yml
Arbitrary strings: ansible-playbook -e key=value
I started out with https://github.com/zsh-users/zsh-completions/blob/master/src/_ansible-playbook which worked decently, but required modifications to support the prefixed file pathing. To achieve this I altered the following lines (the -e line):
...
"(-D --diff)"{-D,--diff}"[when changing (small files and templates, show the diff in those. Works great with --check)]"\
"(-e --extra-vars)"{-e,--extra-vars}"[EXTRA_VARS set additional variables as key=value or YAML/JSON]:extra vars:(EXTRA_VARS)"\
'--flush-cache[clear the fact cache]'\
to this:
...
"(-D --diff)"{-D,--diff}"[when changing (small files and templates, show the diff in those. Works great with --check)]"\
"(-e --extra-vars)"{-e,--extra-vars}"[EXTRA_VARS set additional variables as key=value or YAML/JSON]:extra vars:__at_files"\
'--flush-cache[clear the fact cache]'\
and added the '__at_files' function:
__at_files () {
compset -P #; _files
}
This may be very noobish, but for someone that has never encountered this before, I was pleased that this solved my problem, or so I thought.
This fails me if I have multiple '-e' parameters, which is totally a supported model (similar to how docker allows multiple -v or -p arguments). What this means is that the first '-e' parameter will have my prefixed completion work, but any '-e' parameters after that point become 'dumb' and only allow for normal '_files' completion from what I can tell. So the following will not complete properly:
ansible-playbook -e key=value -e #vars/file
but this would complete for the file itself:
ansible-playbook -e key=value -e vars/file
Did I mess up? I see the same type of behavior for this particular completion plugin's '-M' option (it also becomes 'dumb' and does basic file completion). I may have simply not searched for the correct terminology or combination of terms, or perhaps in the rather complicated documentation missed what covers this, but again, with only a few days experience digging into this, I'm lost.
If multiple -e options are valid, the _arguments specification should start with * so instead of:
"(-e --extra-vars)"{-e,--extra-vars}"[EXTR ....
use:
\*{-e,--extra-vars}"[EXTR ...
The (-e --extra-vars) part indicates a list of options that can not follow the one being specified. So that isn't needed anymore because it is presumably valid to do, e.g.:
ansible-playbook -e key-value --extra-vars #vars/file
Related
I have a grep command that I run daily to find an entry in a huge logfile.
This command works fine in our Development environment. But in our Production environment, it outputs a response that is different from the entry in the logfile.
Here's the command:
logentry=$(grep -m1 -oP '.*(?<=Reset\s).*' $log)
Actual entry in log file:
******Reset Counter:[Total:1849766] [Success:1849766] [Insert:102] [Update:1848861] [Delete:803] [Key:0]
Command output:
******Reset Counter:[Total:1849766] 1 [Insert:102] [Update:1848861] [Delete:803] [Key:0]
Expected output:
******Reset Counter:[Total:1849766] [Success:1849766] [Insert:102] [Update:1848861] [Delete:803] [Key:0]
What could be the reason behind this inconsistent behavior of the grep command?
Thanks #Ed Morton for comment. The fix is working fine.
Root cause:
The variable is not quoted so it's open to globbing, word-splitting, and filename expansion and so the net result will be dependent on files in your directory.
Solution: Use echo "$logentry" instead and ALWAYS quote your shell variabes unless you have a specific purpose in mind by not doing so and fully understand all of the implications.
Security implications of forgetting to quote a variable in bash/POSIX shells
I've been using this utility successfully for many years, in many environemnts. But I'm noticing that on one particular environment, it produces very unexpected results.
grep -r 'search-term1' . | grep 'search-term2'
The above code greps recursively for all instances of search-term1, in the current-dir. The results are then piped to another grep, which selects only those lines that also contain search-term2. This works exactly as I would expect.
grep -r 'search-term1' . | grep -r 'search-term2'
The only difference in the above code is that the -r recursive flag in specified in both grep commands. I would expect the behavior to not change for this particular case. After all, the input to the 2nd grep is a pipe-input, and there's nothing further to be found recursively.
I have been using the command successfully, for many years, in many different environments (both unix and mac-os). However, the most recent environment that I started working in (unix), breaks the above behavior. The second piped grep searches for all instances of search-term2, not only in the piped-input, but also all files in my current directory. Because of this, instead of getting only results that contain both search-terms, I get all results in current-dir that contain the 2nd search term.
Is there any reason why this one particular environment produces this odd behavior? Is there any way I can avoid this, while still preserving the -r flag?
FAQ:
Q: Why am I using the -r flag on a piped input?
Ans: I actually have grep saved as an alias, with many different options and flags that I always want to use as a default. The recursive flag is one of them. I would like to always use this alias, instead of having to type out all the flags every time.
Q: If you want to search for all instances matching both search terms, why not do (insert-superior-method-here) instead?
Ans: You're probably right. I'm sure there are things I can change in my usual habits that would workaround this issue. However, as intellectual curiosity, I would like to find out why recursive-greps-on-pipes work as intended on most environments, but not all, and if that can somehow be resolved.
The -r flag to grep changed in grep version 2.11 (release notes to implicitly use the working directory as the input if no file arguments are given.
If no file operand is given, and a command-line -r or equivalent
option is given, grep now searches the working directory.
You aren't giving the second grep any file arguments so it defaults to the current directory despite there being pipe input.
Try grep -r 'search-term1' . | grep -r 'search-term2' - as a workaround.
grep -r 'search-term1' . | grep -r -d skip 'search-term2' may also work around the problem.
Someone accidentally created a file name '-l' and I cannot remove it, because rm -l interprets the filename as a flag. I've tried quotes, escaping and nothing is working.
In virtually all Unix commandline utilities you can use a double-dash -- to separate options from arguments. Under the hood, getopt will stop attempting to parse arguments as options when it first encounters a --. From the docs:
getopt has three ways to deal with options that follow non-options argv elements. The special argument ‘--’ forces in all cases the end of option scanning.
In your specific case with rm, use:
$ rm -- -l
I would like to issue a patch command which is somewhat dumber than the default, but I cannot find the right flags (if they exist at all).
I don't want it to create .rej or .orig files, not even when the patch fails. If the patch fails I'd like the original files to remain unchanged.
I don't want it to try guessing if the patch is reversed or not, or try matching the lines before or after those given in the patch. If the lines at the given line numbers do not match, it should fail.
I've tried with -f -N -V never -r - --no-backup-if-mismatch, but still backup files are created and "fuzzy" matching is tried.
Run it with --dry-run -s and only apply if it doesn't report any problems (you may be able to key off the return code).
For disabling the fuzz, you need -F0
zsh is great but its completion system is very diverse. And the documentation lacks good examples. Is there a template for completing for a specific application. The completion would get its match data from a file, separated by newlines?
I tried modifying an older example of mine that takes match data "live":
~ % cat .zsh/completers/_jazzup
#compdef jazz_up
_arguments "2: :(`mpc lsplaylists|sed -e 's# #\\\\ #g'`)"
I could supply cat my_file there instead of mpc invocation and so on but would there be a more elegant way to do this simple task? And that completion there is placement-specific: can you provide an example where zsh would attempt to complete at any point after the program name is recognized?
The match data will have whitespaces and so on, the completion should escape the WS. Example of that:
Foo bar
Barbaric
Get it (42)
Now if that completion would be configured for a command Say, we should get this kind of behaviour out of zsh:
$ Say Fo<TAB>
$ Say Foo\ bar
$ Say Ge<TAB>
$ Say Get\ it\ \(42\)
Simple completion needs are better addressed with _describe, it pairs an array holding completion options and a description for them (you can use multiple array/description pairs, check the manual).
(_arguments is great but too complex.)
[...]
First create a file
echo "foo\nbar\nbaz\nwith spac e s\noh:noes\noh\:yes" >! ~/simple-complete
Then create a file _simple somewhere in your $fpath:
#compdef simple
# you may wish to modify the expansion options here
# PS: 'f' is the flag making one entry per line
cmds=( ${(uf)"$(< ~/simple-complete)"} )
# main advantage here is that it is easy to understand, see alternative below
_describe 'a description of the completion options' cmds
# this is the equivalent _arguments command... too complex for what it does
## _arguments '*:foo:(${cmds})'
then
function simple() { echo $* }
autoload _simple # do not forget BEFORE the next cmd!
compdef _simple simple # binds the completion function to a command
simple [TAB]
it works. Just make sure the completion file _simple is placed somewhere in your fpath.
Notice that : in the option list is supposed to be used for separating an option from their (individual) description (oh:noes). So that won't work with _describe unless you quote it (oh\:yes). The commented out _arguments example will not use the : as a separator.
Without changing anything further in .zshrc (I already have autoload -Uz compinit
compinit) I added the following as /usr/local/share/zsh/site-functions/_drush
#compdef drush
_arguments "1: :($(/usr/local/bin/aliases-drush.php))"
Where /usr/local/bin/aliases-drush.php just prints a list of strings, each string being a potential first argument for the command drush. You could use ($(< filename)) to complete from filename.
I based this on https://unix.stackexchange.com/a/458850/9452 -- it's surprising how simple this is at the end of the day.