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Special characters can be utilized as variables in sed in a comprehensive manner by using escape characters along with them. Here are some tips to use special characters as variables in sed:
Use the $
symbol to access a variable's value. For example, to access the value of the variable var
, use $var
.
Use the \\
symbol to escape special characters like .
or *
. For example, if a variable val
contains a regular expression .*
, then use \\.*
instead of .*
in the sed command.
Use single quotes around the sed command to prevent the shell from interpreting any special characters. For example, use 's/'$var'//'
instead of "s/$var//"
.
Use double quotes around the variable to allow sed to interpret any backslash escape characters in the variable. For example, use "s/$var/\n/g"
to substitute all occurrences of the variable var
with a newline character.
Use the -e
option to execute multiple sed commands in one script. For example, sed -e 's/'$var'//' -e 's/abc/'$val'/'
will remove the variable var
and replace any occurrence of abc
with the value of the variable val
.
In summary, using escape characters and proper quoting can allow special characters to be used as variables in sed in a comprehensive manner.