I need to use this code inside a YAML file to remove chars from a file, but on YAML # is comment and cannot execute all after the #
Example of what I want to execute: echo $(tr -d '[\[\]#,"]')
Is there any workaround to achieve want I need?
The easiest, probably, in you case, would be to use a folded block style, because your tr does have simple and double quotes in it, and going with a quoted string would need you to go in escaping characters, which could be a pain.
But for the sake of completeness, here are the possible ways:
foo: "# I am not a comment, as I am enclosed in double quoted string"
bar: '# me neither, as I am enclosed in a single quoted string'
baz: |
# so ain't I, in a literal style block
qux: >
# I don't differ from the three above, in a folded style block
So, in your case, what you could do is:
my_command: >-
echo $(tr -d '[\[\]#,"]')
This is just a matter of YAML syntax. You can enclose your command in single or double quotes and escape inner quotes using a backslash
(\)
For example, using single quotes and using \' to escape the literal inner single quotes:
script:
- 'echo $(tr -d \'[\[\[]#,"]\')'
Or the same with double quotes:
script:
- "echo $(tr -d '[\[\]#,\"]')"
You can also use the other string styles that don't require escaping as described in another answer.
Related
I need use sed into bash script, for add lines after any line numer of script with some pair of values (below work)
sed -i.bak '14i\some_text=some_text' file
But I need on script bash (sh) for expand variables (below not work)
sed -i.bak '$number_linei\$var1=$var2' $var3
Just use double quotes instead of single quotes. You'll also need to use {} to delimit the number_line variable correctly and escape the \, too.
sed -i.bak "${number_line}i\\$var1=$var2" $var3
I'd personally prefer to see all of the variables use the {}, ending up with something like:
sed -i.bak "${number_line}i\\${var1}=${var2}" ${var3}
Change single quotes to double quotes:
man bash:
Enclosing characters in single quotes preserves the literal value of
each character within the quotes.
Enclosing characters in double quotes preserves the literal value of
all characters within the quotes, with the exception of $, `, \, and,
when history expansion is enabled, !. The characters $ and ` retain
their special meaning within double quotes.
I need use sed into bash script, for add lines after any line numer of script with some pair of values (below work)
sed -i.bak '14i\some_text=some_text' file
But I need on script bash (sh) for expand variables (below not work)
sed -i.bak '$number_linei\$var1=$var2' $var3
Just use double quotes instead of single quotes. You'll also need to use {} to delimit the number_line variable correctly and escape the \, too.
sed -i.bak "${number_line}i\\$var1=$var2" $var3
I'd personally prefer to see all of the variables use the {}, ending up with something like:
sed -i.bak "${number_line}i\\${var1}=${var2}" ${var3}
Change single quotes to double quotes:
man bash:
Enclosing characters in single quotes preserves the literal value of
each character within the quotes.
Enclosing characters in double quotes preserves the literal value of
all characters within the quotes, with the exception of $, `, \, and,
when history expansion is enabled, !. The characters $ and ` retain
their special meaning within double quotes.
When querying a list and putting the value in a variable and trying to use the variable in another script it doenst get the format needed.
script 1:
cilist=$(opr-ci-list.sh -view_name TN_UD_REFRESH_MRE | sed -e '/^[TL-]/d' -e '/^\s*$/d' -e 's/^....//' | awk -vORS=, '{ print $1 }' | sed 's/,$/\n/')
The output of this script will be ID's comma seperated string like: 7c553435c1376c8f5f020fcee0b8ef51,7d427dd75235bf513286d3210e1bd787
echo $cilist
7c553435c1376c8f5f020fcee0b8ef51,7d427dd75235bf513286d3210e1bd787
=> no quotes to be seen when doing a echo
script 2:
opr-downtime.sh -cis "\"$cilist\""
i receive an error because the are single quotes surrounding the variable:
-cis '"7c553435c1376c8f5f020fcee0b8ef51,7d427dd75235bf513286d3210e1bd787 "'
I tried several syntax ways but keep getting the wrong input for the second script. Or i have no quotes or quotes like '" in front and behind.
Any help or feedback on the correct syntax would be appreciated.
The shell treats the quote characters as special characters. For double quote ("), it treats the enclosed data as a single argument to the command. This would be useful if the input had a space (or other shell separator token) within it. However, when the argument is provided to the command, the quote is removed.
You can try using backslash (\) to escape the double quote. But, you may still want to enclose everything with a double quote incase $cilist has input that requires quoting.
script.sh -cis "\"$cilist\""
Usually, in order to embed a quotation mark in a string, \ (backslash) is used.
Does a backslash have a different meaning in a Bash script?
My code below isn't working: the quotation mark wasn't included, and the following errors were reported:
recursive_merge.sh: line 7: unexpected EOF while looking for matching `''
recursive_merge.sh: line 14: syntax error: unexpected end of file
I have no explanation. Line 14 doesn't even exist.
#!/bin/bash
#############this file should be in the directory directly upper than p0x. sphnum.txt should also be at the same directory
for i in 02 03 04 05 06 07 09 10 11 12 13 14 15 16 17 20 21 22 23 24 25; do
x=$(grep $i sphnum.txt |cut -c5-6)
y=$(grep $i sphnum.txt |cut -c8-9)
z=$(echo '\''$i'.ala.r'$x'.sph '$i'.ala.r'$y'.sph\'')
w=$(echo $i'.ala.r'$x'r'$y'.sph')
echo $z
echo $w
cd p$i/spheres.10_2_75/sph/
/project/Biogroup/Software/Docking/MergeSpheres.pl -s $z -o $w -n 500 &
cd ../../../
done
As tripleee points out in comments on the question, the best approach in this particular scenario is to use a double-quoted string, in which you can embed both variable references (e.g., $i) and single quotes as-is; e.g.: z="'$i.ala.r$x.sph $i .ala.r$y.sph'"
This answer focuses on the various approaches to producing / embedding literal ' chars. in strings, starting with the OP's misconception.
Your use of '\'' suggests that you're confused by the workaround that is commonly used to "embed" a single quote in an overall single-quoted string, which is not what your code does on the z=... line, because it starts with '\''.
If we simplify your command, we get:
echo '\''$i
which is a syntax error, because to Bash the single quotes are unbalanced, because '\' by itself is considered a complete single-quoted string containing literal \, followed by the opening ' of a second single-quoted string, which is never closed.
Again it's worth noting that "'$i" is the best solution to this specific problem: the ' can be embedded as-is, and including variable reference $i inside the double-quoted string protects its value from potentially unwanted word-splitting and filename expansion (globbing).
POSIX-like shells provide NO way to embed single quotes inside a single-quoted string - not even with escaping. Hence, the \ in '\' is simply treated as a literal (see below for a workaround).
The rest of this answer shows all approaches to producing a literal ', both inside and outside quoted strings.
To create a single quotation mark outside of a quoted string, simply use \':
$ echo I am 6\' tall.
I am 6' tall.
This quotes (escapes) the individual ' character only, using \.
But note that tokens placed outside the context of a single- or double-quoted string on a command line are subject to word-splitting and filename expansion (globbing).
To use a single quote inside a double-quoted string, use it as-is (no escaping needed):
$ echo "I am 6' tall."
I am 6' tall.
This is the best choice if you also want to embed variable references (e.g., $i) or commands (via command substitutions, $(...)) in your string (you can suppress interpolation by escaping $ as \$).
To use a single quote inside a single-quoted string (in which no interpolations (expansions) are performed by design), you must use a workaround:
$ echo 'I am 6'\'' tall.'
I am 6' tall.
The workaround is necessitated by single-quoted strings not supporting embedded single quotes at all; the '\'' part only makes sense "inside" a single-quoted string in that:
the leading ' terminates the single-quoted string so far
the \' then produces a ' literal individually escaped with \ outside the context of a quoted string.
the trailing ' then "restarts" the remainder of the single-quoted string.
In other words: While you cannot directly embed a single quote, you can break the single-quoted string into multiple pieces, insert individually \-escaped ' instances outside the single-quoted string as needed, and let Bash's string concatenation (which automatically joins directly adjacent string) piece it all back together to form a single string.
chepner points out in a comment that you can alternatively use a here-document with a quoted opening delimiter, which acts like a single-quoted string while allowing embedding of ' chars:
read -r var <<'EOF' # quoted delimiter -> like a '...' string, but ' can be embedded
I am 6' tall.
EOF
With an unquoted opening delimiter, the here-document acts like a double-quoted string, which, just like the latter, also allows embedding ', while also supporting expansions:
read -r var <<EOF # unquoted delimiter -> like a "..." string
$USER is 6' tall.
EOF
Finally, if remaining POSIX-compliant is not a must, you can use an ANSI C-quoted string string, which allows embedding single quotes with \';
note that such strings interpret control-character escape sequences such as \n, but otherwise, like a normal single-quoted string, do not perform interpolation of variable references or command substitutions:
$ echo $'I am 6\' tall.'
I am 6' tall.
I need use sed into bash script, for add lines after any line numer of script with some pair of values (below work)
sed -i.bak '14i\some_text=some_text' file
But I need on script bash (sh) for expand variables (below not work)
sed -i.bak '$number_linei\$var1=$var2' $var3
Just use double quotes instead of single quotes. You'll also need to use {} to delimit the number_line variable correctly and escape the \, too.
sed -i.bak "${number_line}i\\$var1=$var2" $var3
I'd personally prefer to see all of the variables use the {}, ending up with something like:
sed -i.bak "${number_line}i\\${var1}=${var2}" ${var3}
Change single quotes to double quotes:
man bash:
Enclosing characters in single quotes preserves the literal value of
each character within the quotes.
Enclosing characters in double quotes preserves the literal value of
all characters within the quotes, with the exception of $, `, \, and,
when history expansion is enabled, !. The characters $ and ` retain
their special meaning within double quotes.