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Full Discussion: escaping backslashes to evaluate paths
Top Forums Shell Programming and Scripting escaping backslashes to evaluate paths Post 302419942 by surfbus78 on Monday 10th of May 2010 06:54:41 AM
Old 05-10-2010
escaping backslashes to evaluate paths
Hi there,

i am struggling with this one, basically i want to replace an existing path string in a file with a new one, but the new one contains slashes which causes problems with "sed", i thought i could change the replacement string into a variable but of course when the variable is evaluated it contains slashes which confuses sed , so i thought i could set the original variable with escaped slashes but it doesn't like this.
the example is:

I want to change a line in a file:
CLASSPATH="/opt/app/example.jar"
to:
CLASSPATH="/opt/app/default.jar"

i was going to use "sed" or perl pie to do this, e.g
sed -e "s/^CLASSPATH.*$/CLASSPATH=\"${CLASSES}\"/g" set.sh >set.out

CLASSES is an environment variable that is populated from a properties file so the sed line above just replaces the whole line that begins with CLASSPATH with the new line based on the variable. but i need to escape the backslashes when the variable is evaluated so that they get pushed into the "sed" command.

any good ideas?

cheers

Steve
 

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LEARN ABOUT DEBIAN

systemd-path

SYSTEMD-PATH(1) 						   systemd-path 						   SYSTEMD-PATH(1)

NAME

       systemd-path - List and query system and user paths

SYNOPSIS

       systemd-path [OPTIONS...] [NAME...]

DESCRIPTION

       systemd-path may be used to query system and user paths. The tool makes many of the paths described in file-hierarchy(7) available for
       querying.

       When invoked without arguments, a list of known paths and their current values is shown. When at least one argument is passed, the path
       with this name is queried and its value shown. The variables whose name begins with "search-" do not refer to individual paths, but instead
       to a list of colon-separated search paths, in their order of precedence.

OPTIONS

       The following options are understood:

       --suffix=
	   The printed paths are suffixed by the specified string.

       -h, --help
	   Print a short help text and exit.

       --version
	   Print a short version string and exit.

EXIT STATUS

       On success, 0 is returned, a non-zero failure code otherwise.

SEE ALSO

       systemd(1), file-hierarchy(7)

systemd 237															   SYSTEMD-PATH(1)
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