Search replace regular expression variable using sed

Question

This is probably a trivial one:

I have a file (my.file) with these lines:

>h1_c1
>h1_c2
>h1_c3
>h2_c1
>h2_c2
>h2_c3

and I want to change it in place to be:

>c1_h1
>c2_h1
>c3_h1
>c1_h2
>c2_h2
>c3_h3

I thought this ought to do it:

sed -i 's/\(\>\)\(h1\)\(\_\)\(.*\)/\1 \4 \3 \2/g' my.file
sed -i 's/\(\>\)\(h2\)\(\_\)\(.*\)/\1 \4 \3 \2/g' my.file

but it doesn't seem to work. How do I do it?

pls confirm that the last line of your output should be c3_h2 not h3 — Kent
– Kent, Commented Mar 13, 2014 at 14:28

Emmet · Accepted Answer · 2014-03-13 14:30:34Z

2

The obvious sed for your example is:

$ sed -i~ -e 's/^>\(h[0-9]\)_\(c[0-9]\)/>\2_\1/' *.foo

I tested this and it works for your example file.

answered Mar 13, 2014 at 14:30

Emmet

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Comments

Jotne · Accepted Answer · 2014-03-13 14:25:06Z

1

Try this awk

awk -F">|_" '{print ">"$3"_"$2}' my.file > tmp && mv tmp my.file

awk -F">|_" '{print ">"$3"_"$2}' my.file
>c1_h1
>c2_h1
>c3_h1
>c1_h2
>c2_h2
>c3_h2

answered Mar 13, 2014 at 14:25

Jotne

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sat · Accepted Answer · 2014-03-13 14:26:10Z

1

You can try this sed,

sed 's/>\(h[1-2]\)_\(.*\)/>\2_\1/' yourfile

(OR)

sed -r 's/>(h[1-2])_(.*)/>\2_\1/' yourfile

answered Mar 13, 2014 at 14:26

sat

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Kent · Accepted Answer · 2014-03-13 14:26:26Z

1

kent$  sed -r 's/>([^_]*)_(.*)/>\2_\1/' f
>c1_h1
>c2_h1
>c3_h1
>c1_h2
>c2_h2
>c3_h2

you add -i if you want it to happen "in-place"

answered Mar 13, 2014 at 14:26

Kent

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