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How to use tr to replace string '-'

I have an output:

--
out1
--
out2
--
out3

I want to get the result:

out1
out2
out3

I thought about using:

tr '--' ''

but it doesn't recognize '-' as the first line I want to replace. How to solve this?

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5 answers 


cat file | sed '/^--/d'


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Why not use it grep -v "^--$" yourfile.txt

?



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another way with awk

awk '!/^--$/' file
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The best you can do with tr

it is to remove the hyphens leaving blank lines. The best way to do what you need is Amro's answer with help sed

. It is important to remember that you tr

are dealing with lists of characters, not multi-character strings, so there is no point in inserting two hyphens in your parameters.

$ tr -d "-" textfile
out1

out2

out3

However, in order for the descriptor to tr

handle hyphens and additional characters, you need to terminate the parameters with --

or place a hyphen after the first character. Let's say you want to get rid of the hyphen and letter-o:

$ tr -d "-o" textfile
tr: invalid option -- 'o'
Try `tr --help' for more information.

$ tr -d -- "-o" textfile
ut1

ut2

ut3

$ tr -d "o-" textfile
ut1

ut2

ut3

It is often useful to use an option terminator --

when the character list is in a variable, so bad data does not create errors unnecessarily. This is true for teams other than tr

.

tr -d -- $charlist $file
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You can do the same with grep

:

cat filename |grep -v "\--"
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