Sed – How to Match Multiple Patterns and Change One Part

sed

I have the below lines in a file:

SUT_INST_PIT=true
SUT_INST_TICS=true
SUT_INST_EXAMPLES=false
SUT_INST_PING=false

How can i create a sed line to match pattern SUT_INST_EXAMPLES & SUT_INST_PING and set false to true?

I can't simply replace false with true because I don't want to change SUT_INST_PIT & SUT_INST_TICS even if they are false!!!

I have at the moment two sed commands that are working, but i would like one line only!

sed -i "s/SUT_INST_EXAMPLES=false/SUT_INST_EXAMPLES=true/g" <file>
sed -i "s/SUT_INST_PING=false/SUT_INST_PING=true/g" <file>

One more thing the sed line should be able to be parametrized to set false->true or true->false, but only for SUT_INST_EXAMPLES & SUT_INST_PING.

Solution (according to @RomanPerekhrest) and how to use it in send (expect script):

send "sed -i 's\/^\\(SUT_INST_EXAMPLES\\|SUT_INST_PING\\)=false\/\\1=true\/' file\r"

Best Answer

sed approach:

sed -i 's/^\(SUT_INST_EXAMPLES\|SUT_INST_PING\)=false/\1=true/' file

file contents:

SUT_INST_PIT=true
SUT_INST_TICS=true
SUT_INST_EXAMPLES=true
SUT_INST_PING=true

\(SUT_INST_EXAMPLES\|SUT_INST_PING\) - alternation group, matches either SUT_INST_EXAMPLES OR SUT_INST_PING at the start of the string

Alternative gawk(GNU awk) approach:

gawk -i inplace -F'=' -v OFS='=' '$1~/^SUT_INST_(EXAMPLES|PING)/{$2=($2=="false")? "true":"false"}1' file

Related Solutions

Sed Command – How to Replace Quotation Marks in a File

Two tips:

You can't escape a single quote within a string quoted with single quotes. So you have to close the quote, add an escaped quote, then open the quotes again. That is: 'foo'\''bar', which breaks down as:
- 'foo' quoted foo
- \' escaped '
- 'bar' quoted bar
yielding foo'bar.
(optional) You don't necessarily have to use / in sed. I find that using / and \ in the same sed expression makes it difficult to read.

For example, to remove the quotes from this file:

$ cat /tmp/f
aaa"bbb"'ccc'aaa

Given my two tips above, the command you can use to remove both double and single quotes is:

$ sed -e 's|["'\'']||g'  /tmp/f

Based on my first tip, the shell reduces sed's second argument (i.e., the string after the -e) to s|["']||g and passes that string to sed. Based on my second tip, sed treats this the same as s/['"]//g. It means

remove all characters matching either ' or " (i.e., replace them with nothing)

You probably need something more complex than this to do what you want, but it's a start.

Sed match pattern and act on x lines after

sed allows us to define ranges of lines and then apply substitutions only within those ranges. We can define a range starting with a line containing Some/Foo/Bar/String and ending with a line containing } and then apply a substitute command to comment out those lines:

$ sed '\|/Some/Foo/Bar/String|,/}/ s/^/#/' file
#foo { '/Some/Foo/Bar/String' :
#    key1 => value1,
#    key2 => value2,
#    key3 => value3,
#    key4 => value4,
#    key5 => value5,
#}

Details

\|/Some/Foo/Bar/String|, /}/

This defines the range. It could have been written as /\/Some\/Foo\/Bar\/String/, /}/ but, to avoid backslashes, I used | as the delimiter in place of / for the first regex.
s/^/#/

This is applied only to lines in the range and it comments them out.

Best Answer

Related Solutions

Sed Command – How to Replace Quotation Marks in a File

Sed match pattern and act on x lines after

Details

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