I'm trying to replace floating-point numbers like 1.2e + 3 with their integer value 1200. For this I use sed in the following way:
echo '"1.2e+04"' | sed "s/\"\([0-9]\+\.[0-9]\+\)e+\([0-9]\+\)\"/$(echo \1*10^\2|bc -l)/"
but the pattern parts \1 and \2 doesn't get evaluated in the echo.
Is there a way to solve this problem with sed?
Thanks in advance
Within the double quotes, \1 and \2 are interpreted as literal 1 and 2.
You need to put additional backslashes to escape them. In addition, $(command substitution) in
sed replacement seems not to work when combined with back references.
If you are using GNU sed, you can instead say something like:
echo '"1.2e+04"' | sed "s/\"\([0-9]\+\.[0-9]\+\)e+\([0-9]\+\)\"/echo \"\\1*10^\\2\"|bc -l/;e"
which yields:
12000.0
If you want to chop off the decimal point, you'll know what to do ;-).
If you are happy with awk command like this can do the work:
echo 1.2e+4|awk '{printf "%d",$0}'
It is perhaps better to use perl (or other typed language) to manage the variable types:
echo '"1.2e+04"' | perl -lane 'my $a=$_;$a=~ s/"//g;print sprintf("%.10g",$a);print $a;'
In any case, your sed expression is incorrect, it should be:
echo '"1.2e+04"' | sed "s/\"\([0-9]\+\.[0-9]\+\)e+\([0-9]\+\)\"/$(echo \1*10^\3 + \2*10^$(echo \3 - 1 | bc -l)|bc -l)/"
The best way to solve the problem properly is to use an advanced combination of # tshiono and # Romeo solutions:
sed "s/\(.*\)\([0-9]\+\.[0-9]\+e+[0-9]\+\)\(.*\)/printf '\1'\; echo \2 |awk '{printf \"%d\",\$0}'\;printf '\3'\;/e"
So it is possible to convert all such floats into arbitrary contexts.
for example:
echo '"1.2e+04"' | sed "s/\(.*\)\([0-9]\+\.[0-9]\+e+[0-9]\+\)\(.*\)/printf '\1'\; echo \2 |awk '{printf \"%d\",\$0}'\;printf '\3'\;/e"
outputs
"12000"
and
echo 'abc"1.2e+04"def' | sed "s/\(.*\)\([0-9]\+\.[0-9]\+e+[0-9]\+\)\(.*\)/printf '\1'\; echo \2 |awk '{printf \"%d\",\$0}'\;printf '\3'\;/e"
outputs
abc"12000"def
I am trying to replace a pipe character in an String with the escaped character in it:
Input: "text|jdbc"
Output: "text\|jdbc"
I tried different things with tr:
echo "text|jdbc" | tr "|" "\\|"
...
But none of them worked.
Any help would be appreciated.
Thank you,
tr is good for one-to-one mapping of characters (read "translate").
\| is two characters, you cannot use tr for this. You can use sed:
echo 'text|jdbc' | sed -e 's/|/\\|/'
This example replaces one |. If you want to replace multiple, add the g flag:
echo 'text|jdbc' | sed -e 's/|/\\|/g'
An interesting tip by #JuanTomas is to use a different separator character for better readability, for example:
echo 'text|jdbc' | sed -e 's_|_\\|_g'
You can take advantage of the fact that | is a special character in bash, which means the %q modifier used by printf will escape it for you:
$ printf '%q\n' "text|jdbc"
text\|jdbc
A more general solution that doesn't require | to be treated specially is
$ f="text|jdbc"
$ echo "${f//|/\\|}"
text\|jdbc
${f//foo/bar} expands f and replaces every occurance of foo with bar. The operator here is /; when followed by another /, it replaces all occurrences of the search pattern instead of just the first one. For example:
$ f="text|jdbc|two"
$ echo "${f/|/\\|}"
text\|jdbc|two
$ echo "${f//|/\\|}"
text\|jdbc\|two
You can try with awk:
echo "text|jdbc" | awk -F'|' '$1=$1' OFS="\\\|"
How can I insert a ',' after the 2nd character ',' at each line ?
I want the following :
input.txt
a,b,c,d,e
e,f,g,
h,,i
output.txt
a,b,,c,d,e
e,f,,g
h,,,i
Thanks in advance
input
$ cat input
a,b,c,d,e
e,f,g,
h,,i
using sed like:
$ N=2
$ cat input | sed "s/,/&,/${N}"
a,b,,c,d,e
e,f,,g,
h,,,i
$ N=3
$ cat input | sed "s/,/&,/${N}"
a,b,c,,d,e
e,f,g,,
h,,i
you can change the N.
s/pattern/replacement/flags
Substitute the replacement string for the pattern.
The value of flags in substitute function is zero or more of the following:
N Make the substitution only for the N'th occurrence
g Make the substitution for all
for function s/,/&,/${N}, it is find the N'th comma and replace it with two commas (An ampersand (&) appearing in the replacement is replaced by the pattern string). And ${N} just is a variable.
BTW, you need to escape the special character double quote if you want to insert ,""
awk to the rescue!
$ awk -F, -v OFS=, '{$3=OFS $3}1' file
a,b,,c,d,e
e,f,,g,
h,,,i
after second , is the third field. Prefix the third field with , and print.
Or, making the column number a parameter and writing delimiter once.
$ awk -F, -v c=3 'BEGIN{OFS=FS} {$c=OFS $c}1' file
This can be read as "insert a new column at position 3". Note that this will also work, adding the 6th column, which will be hard to replicate with sed.
$ awk -F, -v c=6 'BEGIN{OFS=FS} {$c=OFS $c}1' file
a,b,c,d,e,,
e,f,g,,,,
h,,i,,,,
Using sed:
sed -E 's/^([^,]*,[^,]*,)(.*)/\1,\2/' file.txt
Example:
% cat file.txt
a,b,c,d,e
e,f,g,
h,,i
% sed -E 's/^([^,]*,[^,]*,)(.*)/\1,\2/' file.txt
a,b,,c,d,e
e,f,,g,
h,,,i
You can use sed like this:
sed 's/^[^,]*,[^,]*/&,/' file
a,b,,c,d,e
e,f,,g,
h,,,i
I have bunch of string like "{one}two", where "{one}" could be different and "two" is always the same. I need to replace original sting with "three{one}", "three" is also constant. It could be easily done with python, for example, but I need it to be done with shell tools, like sed or awk.
If I understand correctly, you want:
{one}two --> three{one}
{two}two --> three{two}
{n}two --> three{n}
SED with a backreference will do that:
echo "{one}two" | sed 's/\(.*\)two$/three\1/'
The search store all text up to your fixed string, and then replace with the your new string pre-appended to the stored text. SED is greedy by default, so it should grab all text up to your fixed string even if there's some repeat in the variable part (e.gxx`., {two}two will still remap to three{two} properly).
Using sed:
s="{one}two"
sed 's/^\(.*\)two/three\1/' <<< "$s"
three{one}
echo "XXXtwo" | sed -E 's/(.*)two/three\1/'
Here's a Bash only solution:
string="{one}two"
echo "three${string/two/}"
awk '{a=gensub(/(.*)two/,"three\\1","g"); print a}' <<< "{one}two"
Output:
three{one}
awk '/{.*}two/ { split($0,s,"}"); print "three"s[1]"}" }' <<< "{one}two"
does also output
three{one}
Here, we are using awk to find the correct lines, and then split on "}" (which means your lines should not contain more than the one to indicate the field).
Through GNU sed,
$ echo 'foo {one}two bar' | sed -r 's/(\{[^}]*\})two/three\1/g'
foo three{one} bar
Basic sed,
$ echo 'foo {one}two bar' | sed 's/\({[^}]*}\)two/three\1/g'
foo three{one} bar
I try to capitalize the first letter in a CSV which is sorted like this:
a23;asd23;sdg3
What i want is a output like this
a23;Asd23;Sdg3
So the first String should be as is, but the second and third should have a capitalized first letter. I tried with AWK and SED but i didn't find the right solution. Can someone help?
Just capitilise all letters that follow a semicolon:
sed -e 's/;./\U&\E/g'
Bash (version 4 and up) has a "first uppercase" operator, ${var^}, but in this case I think it is better to use sed:
sed -r 's/(^|;)(.)/\1\U\2/g' <<< "a23;asd23;sdg3"
echo "a23;asd23;sdg3" | perl -ne 's/(?<=\W)(\w)/ uc($1) /gex;print $_'
a23;Asd23;Sdg3
$ var="a23;asd23;sdg3"
$ echo $var | awk -F";" '{for(i=2;i<=NF;i++) $i=toupper(substr($i,i,1))substr($i,1) }1' OFS=";"
a23;Sasd23;Gsdg3