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BeMy Friend
Asked: 2014-10-25 14:46:35 +0800 CST

SED \n and \ into nothing

  • 772

The people on this forum have been a tremendous help! Thank you so much!

Here is my string

UEsDBBQAAAAIAKJBWEUdUIwScwwBAAB+AQAgAAAAQ29weV9vZl9kb2N1bWVudF9PY3QtMjQtMjAx\nNC5leGXsvXlcU0f0N5xAgICBRAVFRaVK3XfAigFFJYALGkSCKItWRMQNMVHrCl6ihGvc6lq1laKt\na11q3ZcgyKKouG+o2KJeDCoqCgpyn3Pm3ovY5X1\/zz\/

I'm trying to remove the \n and the \ from the above string.

I've tried:

tr ‘\n\r\\’ ‘   ‘

sed 's/\n//g;s;\\;;g'

And a few other variations, but I'm not successful in stripping everything. I can get the \ but not the n.

Does anyone see my error?

command-line

3 Answers

  1. Try:

    sed 's/\\n//g;s/\\//g'

    You want to remove a literal \ followed by a literal n. Consequently, the backslash has to be escaped in the first substitution. By contrast, s/\n//g would remove newline characters.

    • 6

  2. Use this with tr to delete (-d) all \n and \:

    tr -d '\\n\\'

    Test:

    echo 'foo\nbar\foo' | tr -d '\\n\\'

    Output:

    foobarfoo
    • 2

  3. You could do simply like this. You don't need to have another substitution.

    sed 's/\\n\|\\//g'

    OR

    sed 's~\\n\|\\~~g'

    Example:

    $ var='UEsDBBQAAAAIAKJBWEUdUIwScwwBAAB+AQAgAAAAQ29weV9vZl9kb2N1bWVudF9PY3QtMjQtMjAx\nNC5leGXsvXlcU0f0N5xAgICBRAVFRaVK3XfAigFFJYALGkSCKItWRMQNMVHrCl6ihGvc6lq1laKt\na11q3ZcgyKKouG+o2KJeDCoqCgpyn3Pm3ovY5X1\/zz\/'
$ sed 's/\\n\|\\//g' <<<"$var"
UEsDBBQAAAAIAKJBWEUdUIwScwwBAAB+AQAgAAAAQ29weV9vZl9kb2N1bWVudF9PY3QtMjQtMjAxNC5leGXsvXlcU0f0N5xAgICBRAVFRaVK3XfAigFFJYALGkSCKItWRMQNMVHrCl6ihGvc6lq1laKta11q3ZcgyKKouG+o2KJeDCoqCgpyn3Pm3ovY5X1/zz/

    Explanation:

    Syntax of sed:

    sed 's/pattern/replace/modifier' file

    Command:

    Splitted the above sed command like below for clarification.

    sed 's/\\n\|\\//g'
    • s - search and substitute.
    • \\n\|\\ - Pattern . \\n match a literal \n OR \| match a literal \. So at first it matches all the \n in the input string and then matches \
    • // We have an empty replacement part, which means remove all the matched characters or replace the matched characters with an empty string.
    • g - Global modifier. It makes the match to happen globally. ie, if two or more \ symbols present on a single line, this sed 's/\\//' file removes only the first \ for each line. But the global modifier g forces sed to match all the existing \ symbols.

    Through GNU sed,

    $ sed -r 's/\\n|\\//g' <<<"$var"
UEsDBBQAAAAIAKJBWEUdUIwScwwBAAB+AQAgAAAAQ29weV9vZl9kb2N1bWVudF9PY3QtMjQtMjAxNC5leGXsvXlcU0f0N5xAgICBRAVFRaVK3XfAigFFJYALGkSCKItWRMQNMVHrCl6ihGvc6lq1laKta11q3ZcgyKKouG+o2KJeDCoqCgpyn3Pm3ovY5X1/zz/

    Through Perl,

    $ perl -pe 's/\\n?//g' <<<"$var"
UEsDBBQAAAAIAKJBWEUdUIwScwwBAAB+AQAgAAAAQ29weV9vZl9kb2N1bWVudF9PY3QtMjQtMjAxNC5leGXsvXlcU0f0N5xAgICBRAVFRaVK3XfAigFFJYALGkSCKItWRMQNMVHrCl6ihGvc6lq1laKta11q3ZcgyKKouG+o2KJeDCoqCgpyn3Pm3ovY5X1/zz/
    • 1