Shell – How to echo an expression with both single and double quotes

echoquotingshell

I have tried many things, but I'm new to the shell. Is it possible to have both double and single quotes within an echo?

I want to generate echo "scan 'LPV',{FILTER => "(PrefixFilter ('MP1-Eq1')"}" for system call, but I am getting an error because of the mutiple double and single quotes.

ftable="echo" " \"" "scan" " " "'LPV',{FILTER => " "\"" "\(" "PrefixFilter ""\(""'MP1-Eq1'" "\)" "\"" "\}" "\" "    
echo "scan 'LPV',{FILTER => "(PrefixFilter ('MP1-Eq1')"}"
bash: syntax error near unexpected token `('

How can I write scan 'LPV',{FILTER => "(PrefixFilter ('MP1-Eq1')"}? The syntax is hbase's and I can't change it…

EDIT

I want to call echo within system call.

ftable="echo "scan 'LPV',{FILTER => "(PrefixFilter ('MP1-Eq1')"}" "
system(ftable)
error

I have tried with $ but

ftable="echo $'scan" "\'" "LPV" "\'" ",{FILTER => " "\"" "(PrefixFilter (" "\'" "MP1-Eq1" "\'" ")" "\"" "}' '"
system(ftable)
error

Getting an error because of double quote.

Best Answer

In bash:

echo $'scan \'LPV\',{FILTER => "(PrefixFilter (\'MP1-Eq1\')"}'

echo "scan 'LPV',{FILTER => \"(PrefixFilter ('MP1-Eq1')\"}'"

For longer strings this may be a more convinient alternative:

> cat <<EOT
scan 'LPV',{FILTER => "(PrefixFilter ('MP1-Eq1')"}
EOT

with EOT or \EOT, depending on whether parameter expansion and quote removal (backslash) are intended or not.

Usage within awk

Defining this string within awk would make everything even more complex. This should be done outside awk in the shell:

ftable=$'echo "scan \'LPV\',{FILTER => "(PrefixFilter (\'MP1-Eq1\')"}"'
# echo "$ftable"
awk -v ftable="$ftable" '... system(ftable); ...'

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Vim – How to escape filename containing single and double quotes mix

From :help filename-modifiers:

The file name modifiers can be used after "%", "#", "#n", "<cfile>", "<sfile>",
"<afile>" or "<abuf>".  ...

...
    :s?pat?sub?
            Substitute the first occurrence of "pat" with "sub".  This
            works like the |:s| command.  "pat" is a regular expression.
            Any character can be used for '?', but it must not occur in
            "pat" or "sub".
            After this, the previous modifiers can be used again.  For
            example ":p", to make a full path after the substitution.
    :gs?pat?sub?
            Substitute all occurrences of "path" with "sub".  Otherwise
            this works like ":s".

So rather than just handling double quotes or single quotes, let's just backslash escape everything unusual:

:!ls -l %:gs/[^0-9a-zA-Z_-]/\\&/

Works perfectly with the test filename you provided.

To use an absolute path, which you may want for rsync, you can add :p at the end:

:!ls -l %:gs/[^0-9a-zA-Z_-]/\\&/:p

Actually, it also works just fine if you backslash-escape literally every character, and it's shorter to type:

:!ls -l %:gs/./\\&/:p

So, in your rsync command, instead of %, use %:gs/./\\&/:p.

Bash – Syntax error near unexpected token `done’

Either the do should appear on a new line, or it needs to have a semi-colon inserted in front of it
<FIRST-LAST> should actually be the name of a shell variable, and FIRST-LAST should be a reference to that variable. < and > are not legal characters for shell variables, so we can deduce that something else must be substituted here instead. person seems to be as good a variable name as any in this particular case.

I think something like this should work much better:

while read person ; do
        echo "${person}"
        curl -O "https://www.uoguelph.ca/arts/history/people/${person}"
done < formatted_history.txt

This assumes that the file formatted_history.txt actually exists in the current directory and is a list of people from the https://www.uoguelph.ca/arts/history/people/ page - something like:

tara-abraham
donna-andrew
susan-armstrong-reid
... etc ...

Best Answer

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Bash – Syntax error near unexpected token `done’

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