I am trying to create a code block snippet for Markdown in Emacs.
I tried to create a snippet like so:
# -*- mode: snippet -*-
# name: code-block
# key: cb
# ---
```${1:r}
${2:code}
```
but when I tried to save, it threw an error saying wrong type argument: stringp, nil.
How can I get this snippet to work?
You'll have to escape the backticks with a backslash.
From the documentation:
Plain Text
Arbitrary text can be included as the content of a template. They are usually interpreted as plain text, except $ and `. You need to use \ to escape them: \$ and \` . The \ itself may also needed to be escaped as \\ sometimes.
Related
I'm aware that, in PowerShell, backticks(`) are used to escape characters instead of the backslash(\). Hence, when using sed, this:
echo '"where am I"' | sed "s/\"[^\"]*\"/\033[96m&\033[0m/g;"
will not work and I would have to write it like this:
echo '"where am I"' | sed "s/`"[^\`"]*`"/`e[96m&`e[0m/g;"
Hence, I would like to do the same with this code:
echo '[where am I]' | sed "s/\[\([^09]\)/\033[94m[\033[0m\1/g;"
The expected output should be:
However, when I tried to replace all the backslashes(\) with backticks(`), I can't seem to get the expected output as you can see below:
Any help would be appreciated. Thanks in advance.
As far as I'm aware, GNU sed doesn't support octal escape sequences - such as \033 to represent an ESC char. - only hexadecimal ones - such as \x1b.
The following command, which uses hex. escape sequences, should therefore work in both POSIX-compatible shells and in PowerShell:
# Note: Requires *GNU* sed
(echo '[where am I]' | sed 's/\[\([^09]\)/\x1b[94m[\x1b[0m\1/g')
In other words:
Because the entire, verbatim string ('...') is interpreted by sed itself, there is no need for PowerShell's string interpolation (via "...").
Note:
The enclosing (...), which on Windows is required for Windows PowerShell to properly render the ANSI escape codes / VT (Virtual Terminal) sequences in the terminal (console) - see this answer. It isn't needed if you capture the output in a variable or redirect it.
In PowerShell, use of echo - a built in alias of the Write-Output cmdlet - isn't necessary and can be omitted, due to PowerShell's implicit output behavior.
If your sed implementation doesn't support escape sequences such as \x1b - such as on macOS - you must indeed resort to using PowerShell's escape sequences inside an expandable (double-quoted) string ("..."); that is, you must replace \x1b with escape sequence `e in order to embed a verbatim ESC character into the string, up front (in Windows PowerShell, which doesn't support `e, use subexpression $([char] 0x1b) instead):
# Note: `e only works in PowerShell (Core) 7+
# In Windows PowerShell, use $([char] 0x1b)
(echo '[where am I]' | sed "s/\[\([^09]\)/`e[94m[`e[0m\1/g")
Important: The above commands contain no embedded " characters, which avoids a long-standing PowerShell bug that is still present as of PowerShell (Core) 7.2.2:
The need to unconditionally, manually \-escape embedded " chars. in arguments passed to external programs - see this answer for details.
A few quick examples that print verbatim 3" of snow:
# Up to at least PowerShell 7.2.2:
# Without escaping the embedded " with \ (too),
# they would in effect be removed from the arguments.
# Note that pipeline input is *not* affected.
'3" of snow' | findstr '\"' # Windows
/bin/echo '3\" of snow' # Unix
# In expandable (double-quoted) strings, you therefore must escape *twice*:
# once for PowerShell, then for the external-program call.
'3" of snow' | findstr "\`"" # Windows
/bin/echo "3\`" of snow" # Unix
You can pass non-interpolated expression strings to sed by using single quotes, '; e.g., 'a non-interpolated string'. instead of double quotes around the text. sed would take what it normally does for input. When you use double quotes, that's when powershell escaping comes into play.
Anyway, an alternative to sed would be leveraging the regular expression substitution built into powershell. For instance,
Write-Output ('[where am i]' -replace '\[(.*?)\]', "<<`e[5;36m`$1`e[0m>>")
Will capture the text between square brackets and place it between "chevrons" and make it blink.
Here's an article on inserting ANSI in text using powershell.
Hello I have the following code snippet:
while True:
try:
entry = input("Input element: ")
print (entry)
with open(fileName,'a',encoding='UTF-8') as thisFile:
thisFile.write(entry)
except KeyboardInterrupt:
break
This one basically continuously gets input and writes it to a file until manually interrupted. However, when the user inputs something like a Ñ. It outputs: UnicodeEncodeError: 'utf-8' codec can't encode characters in position 0-1: surrogates not allowed I explicity put the utf-8 encoding and even tried latin-1 but still the same error. I have also put the # -*- coding: utf-8 -*- on top of my code and tried thisFile.write(entry.encode('utf-8') but it still gives me the error.
Setting the following environment variables fixed it for me.
export LANG=C.UTF-8
export LC_ALL=C.UTF-8
or another method is running it via:
PYTHONIOENCODING="UTF-8" python3 writetest.py
I've been using doxygen for a little while now. The editor(N++) I use creates doxygen comments with backslashes for the special commands.
The doxygen manual says:
All commands in the documentation start with a backslash ( \ ) or an at-sign ( # ). If you prefer you can replace all commands starting with a backslash below by their counterparts that start with an at-sign.
So doxygen doesn't really care about it.
Or causes using a \ more trouble than using an #.
The backslash is used as an escape character in C/C++, so that '\"' is a double quote character for example.
Using # for doxygen tags makes it easier to use grep / search the source code.
I always use # for this reason.
I am trying to use a sed command to replace specials characters in my file.
The characters are %> to replace by ].
I'am using sed -r s/\%>\/\]\/g but i have this error bash: /]/g: No such file or directory, looks like sed doesn't like it.
Put your sed code inside quotes and also add the file-path you want to work with and finally don't escape the sed delimiters.
$ echo '%>' | sed 's/%>/]/g'
]
ie,
sed 's/%>/]/g' file
To complement Avinash Raj's correct and helpful answer:
Since you were using an overall unquoted string (neither single- nor double-quoted), you were on the right track by \-escaping individual characters in your sed command.
However, you neglected to \-quote >, which is what caused your problem:
> is one of the shell's so-called metacharacters
Metacharacters have special meaning and separate words
Thus, s/\%>\/\]\/g is mistakenly split into 2 arguments by >:
s/\% is passed to sed - as s/%, because the shell removes the \ instances (a process called quote removal).
As you can see, this is not a valid sed command, but that doesn't even come into play - see below.
>\/\]\/g is interpreted by the shell (bash), because it starts with output-redirection operator >; after quote removal, the shell sees >/]/g, tries to open file /]/g for writing, and fails, because your system doesn't have a subdirectory named ] in its root directory.
bash tries to open an output file specified by a redirection before running the command and, if it fails to open the file, does not run the command - which is what happened here:
bash complained about the nonexistent target directory and aborted processing of the command - sed was never even invoked.
Upshot:
In a string that is neither enclosed in single nor in double-quotes, you must \-quote:
all metacharacters: | & ; ( ) < > space tab
additionally, to prevent accidental pathname expansion (globbing): * ? [
Also note that if you need to quote (escape) characters for sed,you need to add an extra layer of quoting; for instance to instruct sed to use a literal . in the regex, you must pass \\. - two backslashes - so that sed sees the properly escaped \..
Given the above, it is much simpler to (habitually) use single quotes around your sed command, because it ensures that the string is passed as is to sed.
Let's compare a working version of your command to the one from Avinash Raj's answer (leaving out the -r for brevity):
sed s/\%\>\/\]\/g # ok - all metachars. \-quoted, others are, but needn't be quoted
sed s/%\>/]/g # ok - minimum \-quoting
sed 's/%>/]/g' # simplest: single-quoted command
I'm not sure whether I got the question correctly. If you want to replace either % or > by ] then sed is not required here. Use tr in this case:
tr '%>' ']' < input.txt
If you want to replace the sequence %> by ] then the sed command as shown by #AvinashRaj is the way to go.
I want to open a text file in notepad++ in a particular line number. If I do this in cmdline the command should be:
start notepad++ "F:\Path\test.txt" -n100
And it is working fine from command line. Now I have to do this from tcl. But I can't make this command work with exec. When I try to execute this:
exec "start notepad++ \"F:\Path\test.txt\" -n100"
I am getting this error:
couldn't execute "start notepad++ "F:\Path\test.txt" -n100": no such file or directory.
What am I missing. Please guide.
Similar to this question:
exec {*}[auto_execok start] notepad++ F:/Path/test.txt -n10
First, you need to supply each argument of the command as separate values, instead of a single string/list. Next, to mimic the start command, you would need to use {*}[auto_execok start].
I also used forward slashes instead of backslashes, since you would get a first level substitution and get F:Path est.txt.
EDIT: It escaped me that you could keep the backslashes if you used braces to prevent substitution:
exec {*}[auto_execok start] notepad++ {F:\Path\test.txt} -n10
You can simply surround the entire exec statement in curly braces. Like this:
catch {exec start notepad++.exe f:\Path\test.txt -n10}
I haven't found a perfect solution to this yet. All my execs seem to be different from each other. On windows there are various issues.
Preserving double quotes around filename (or other) arguments.
e.g. in tasklist /fi "pid eq 2060" /nh the quotes are required.
Preserving spaces in filename arguments.
Preserving backslash characters in filename arguments.
[Internally, Windows doesn't care whether pathnames have / or \, but some programs will parse the filename arguments and expect the backslash character].
The following will handle the backslashes and preserve spaces, but will not handle double-quoted arguments. This method is easy to use. You can build up the command line using list and lappend.
set cmd [list notepad]
set fn "C:\\test 1.txt"
lappend cmd $fn
exec {*}$cmd
Using a string variable rather than a list allows preservation of quoted arguments:
set cmd [auto_execok start]
append cmd " notepad"
append cmd " \"C:\\test 1.txt\""
exec {*}$cmd
Note that if you need to supply the full path to the command to be executed, it often needs to be quoted also due to spaces in the pathname:
set cmd "\"C:\\Program Files\\mystuff\\my stuff.exe\" "