grep only one occurrence - linux

I am trying to grab some content, but there are multiple instances of it in the same line. I am using this command.
grep -o -m 1 -P '(?<=sk).*(?=fa)' test.txt | head -1
However, the search ends after the second/last match. Running it on Ubuntu 14.04.2
test.txt: skjahfasdkl aklsdj laks skjahfasdkl aklsdj laks
Current Output: jahfasdkl aklsdj laks skjah
Desired output: jah

You just need non-greedy:
grep -m1 -oP '(?<=sk).*?(?=fa)' file | head -1
# ...................^^^
The -m1 will stop after the first line, but you still need head to limit to the first match.

It's greedy match, you want to treat space as delimiters so specify the match to nonspace chars, i.e.
... '(?<=sk)[^ ]*(?=fa)'

if the condition is non spaces between sk and fa ( matching in words ), you can use can use [^ ]* instead .*, as the following:
grep -o -m 1 -P '(?<=sk)[^ ]*(?=fa)' test.txt | head -1
else you can use this :
sed -e "s/sk\(.*\)fa.*$/\1/g" test.txt | sed -e "s/fa.*$//g"
test :
echo "skjahz z zfasdkl aklsdj laks skjahppppfasdkl aklsdj laks" | sed -e "s/sk\(.*\)fa.*$/\1/g" | sed -e "s/fa.*$//g"
#jahz z z

If you consider non-grep answer then this gnu-awk can do the job:
awk -v FPAT='sk[^[:blank:]]*fa' '{gsub(/^sk|fa$/, "", $1); print $1; exit}' file

Related

Bash issue with floating point numbers in specific format

(Need in bash linux)I have a file with numbers like this
1.415949602
91.09582241
91.12042924
91.40270349
91.45625033
91.70150341
91.70174342
91.70660043
91.70966213
91.72597066
91.7287678315
91.7398645966
91.7542977976
91.7678146465
91.77196659
91.77299733
abcdefghij
91.7827827
91.78288651
91.7838959
91.7855
91.79080605
91.80103075
91.8050505
sed 's/^91\.//' file (working)
Any way possible I can do these 3 steps?
1st I try this
cat input | tr -d 91. > 1.txt (didnt work)
cat input | tr -d "91." > 1.txt (didnt work)
cat input | tr -d '91.' > 1.txt (didnt work)
then
grep -x '.\{10\}' (working)
then
grep "^[6-9]" (working)
Final 1 line solution
cat input.txt | sed 's/\91.//g' | grep -x '.\{10\}' | grep "^[6-9]" > output.txt
Your "final" solution:
cat input.txt |
sed 's/\91.//g' |
grep -x '.\{10\}' |
grep "^[6-9]" > output.txt
should avoid the useless cat, and also move the backslash in the sed script to the correct place (and I added a ^ anchor and removed the g flag since you don't expect more than one match on a line anyway);
sed 's/^91\.//' input.txt |
grep -x '.\{10\}' |
grep "^[6-9]" > output.txt
You might also be able to get rid of at least one useless grep but at this point, I would switch to Awk:
awk '{ sub(/^91\./, "") } /^[6-9].{9}$/' input.txt >output.txt
The sub() does what your sed replacement did; the final condition says to print lines which match the regex.
The same can conveniently, but less readably, be written in sed:
sed -n 's/^91\.([6-9][0-9]\{9\}\)$/\1/p' input.txt >output.txt
assuming your sed dialect supports BRE regex with repetitions like [0-9]\{9\}.

In bash, how to sort strings including numbers?

I have a script that outputs file paths (via find) :
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3-something16
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something1
/foo/bar/example/foo/bar/example/foo-bar-example/1.2-something5
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something2
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something10
How can I list them in Bash so that they are in ascending numeric order based on the number at the end and regardless of the version ( 1.2, 1.2.3 or 1.2.3.4)
Ps : the something part can eventually contain a dash.
Desired output :
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something1
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something2
/foo/bar/example/foo/bar/example/foo-bar-example/1.2-something5
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something10
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3-something16
I used a temporary sentinel character to delimit the number at the end but it's a little bit complicated in my case.
Extract the number at the end, prepend it to all the lines, sort numerically and finally delete that number:
sed -r 's/(.*)([^0-9])([0-9]+)$/\3\1\2\3/' file | sort -n | sed 's/^[0-9]*//'
With your input, this returns:
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something1
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something2
/foo/bar/example/foo/bar/example/foo-bar-example/1.2-something5
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something10
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3-something16
I think this is the Schwartzian transform.
By pieces:
$ sed -r 's/(.*)([^0-9])([0-9]+)$/\3\1\2\3/' a
16/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3-something16
1/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something1
5/foo/bar/example/foo/bar/example/foo-bar-example/1.2-something5
2/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something2
10/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something10
#^
#note the numbers here
$ sed -r 's/(.*)([^0-9])([0-9]+)$/\3\1\2\3/' a | sort -n
1/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something1
2/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something2
5/foo/bar/example/foo/bar/example/foo-bar-example/1.2-something5
10/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something10
16/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3-something16
# ^
# now it is ordered
$ sed -r 's/(.*)([^0-9])([0-9]+)$/\3\1\2\3/' a | sort -n | sed 's/^[0-9]*//'
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something1
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something2
/foo/bar/example/foo/bar/example/foo-bar-example/1.2-something5
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something10
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3-something16
You can use this sed + sort + awk:
sed -E 's/.*[^0-9]([0-9]+)$/\1 &/' file | sort -n | awk '{print $2}'
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something1
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something2
/foo/bar/example/foo/bar/example/foo-bar-example/1.2-something5
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3.4-something10
/foo/bar/example/foo/bar/example/foo-bar-example/1.2.3-something16
If you can ensure that you will never have a '#' character in your file, you can try:
sed -e 's/something/#/g' filename.txt | sort -t# -k2 -n | sed -e 's/#/something/g'

How to make GREP select only numeric values?

I use the df command in a bash script:
df . -B MB | tail -1 | awk {'print $4'} | grep .[0-9]*
This script returns:
99%
But I need only numbers (to make the next comparison).
If I use the grep regex without the dot:
df . -B MB | tail -1 | awk {'print $4'} | grep .[0-9]*
I receive nothing.
How to fix?
If you try:
echo "99%" |grep -o '[0-9]*'
It returns:
99
Here's the details on the -o (or --only-matching flag) works from the grep manual page.
Print only the matched (non-empty) parts of matching lines, with each such part on a separate output line. Output lines use the same delimiters as input, and delimiters are null bytes if -z (--null-data) is also used (see Other Options).
grep will print any lines matching the pattern you provide. If you only want to print the part of the line that matches the pattern, you can pass the -o option:
-o, --only-matching
Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.
Like this:
echo 'Here is a line mentioning 99% somewhere' | grep -o '[0-9]+'
How about:
df . -B MB | tail -1 | awk {'print $4'} | cut -d'%' -f1
No need to used grep here, Try this:
df . -B MB | tail -1 | awk {'print substr($5, 1, length($5)-1)'}
function getPercentUsed() {
$sys = system("df -h /dev/sda6 --output=pcent | grep -o '[0-9]*'", $val);
return $val[0];
}
Don't use more commands than necessary, leave away tail, grep and cut. You can do this with only (a simple) awk
PS: giving a block-size en print only de persentage is a bit silly ;-) So leave also away the "-B MB"
df . |awk -F'[multiple field seperators]' '$NF=="Last field must be exactly --> mounted patition" {print $(NF-number from last field)}'
in your case, use:
df . |awk -F'[ %]' '$NF=="/" {print $(NF-2)}'
output: 81
If you want to show the percent symbol, you can leave the -F'[ %]' away and your print field will move 1 field further back
df . |awk '$NF=="/" {print $(NF-1)}'
output: 81%
You can use Perl style regular expressions as well. A digit is just \d then.
grep -Po "\\d+" filename
-P Interpret PATTERNS as Perl-compatible regular expressions (PCREs).
-o Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.

How to read the second-to-last line in a file using Bash?

I have a file that has the following as the last three lines. I want to retrieve the penultimate line, i.e. 100.000;8438; 06:46:12.
.
.
.
99.900; 8423; 06:44:41
100.000;8438; 06:46:12
Number of patterns: 8438
I don't know the line number. How can I retrieve it using a shell script? Thanks in advance for your help.
Try this:
tail -2 yourfile | head -1
A short sed one-liner inspired by https://stackoverflow.com/a/7671772/5287901
sed -n 'x;$p'
Explanation:
-n quiet mode: dont automatically print the pattern space
x: exchange the pattern space and the hold space (hold space now store the current line, and pattern space the previous line, if any)
$: on the last line, p: print the pattern space (the previous line, which in this case is the penultimate line).
Use this
tail -2 <filename> | head -1
ed and sed can do it as well.
str='
99.900; 8423; 06:44:41
100.000;8438; 06:46:12
Number of patterns: 8438
'
printf '%s' "$str" | sed -n -e '${x;1!p;};h' # print last line but one
printf '%s\n' H '$-1p' q | ed -s <(printf '%s' "$str") # same
printf '%s\n' H '$-2,$-1p' q | ed -s <(printf '%s' "$str") # print last line but two
From: Useful sed one-liners by Eric Pement
# print the next-to-the-last line of a file
sed -e '$!{h;d;}' -e x # for 1-line files, print blank line
sed -e '1{$q;}' -e '$!{h;d;}' -e x # for 1-line files, print the line
sed -e '1{$d;}' -e '$!{h;d;}' -e x # for 1-line files, print nothing
You don't need all of them, just pick one.
tail +2 <filename>
This prints from second line to last line.
To clarify what has already been said:
ec2thisandthat | sort -k 5 | grep 2012- | awk '{print $2}' | tail -2 | head -1
snap-e8317883
snap-9c7227f7
snap-5402553f
snap-3e7b2c55
snap-246b3c4f
snap-546a3d3f
snap-2ad48241
snap-d00150bb
returns
snap-2ad48241
tac <file> | sed -n '2p'

Get line number while using grep

I am using grep recursive to search files for a string, and all the matched files and the lines containing that string are print on the terminal. But is it possible to get the line numbers of those lines too??
ex: presently what I get is /var/www/file.php: $options = "this.target", but what I am trying to get is /var/www/file.php: 1142 $options = "this.target";, well where 1142 would be the line number containing that string.
Syntax I am using to grep recursively is sudo grep -r 'pattern' '/var/www/file.php'
One more question is, how do we get results for not equal to a pattern. Like all the files but not the ones having a certain string?
grep -n SEARCHTERM file1 file2 ...
Line numbers are printed with grep -n:
grep -n pattern file.txt
To get only the line number (without the matching line), one may use cut:
grep -n pattern file.txt | cut -d : -f 1
Lines not containing a pattern are printed with grep -v:
grep -v pattern file.txt
If you want only the line number do this:
grep -n Pattern file.ext | gawk '{print $1}' FS=":"
Example:
$ grep -n 9780545460262 EXT20130410.txt | gawk '{print $1}' FS=":"
48793
52285
54023
grep -A20 -B20 pattern file.txt
Search pattern and show 20 lines after and before pattern
grep -nr "search string" directory
This gives you the line with the line number.
In order to display the results with the line numbers, you might try this
grep -nr "word to search for" /path/to/file/file
The result should be something like this:
linenumber: other data "word to search for" other data
When working with vim you can place
function grepn() {
grep -n $# /dev/null | awk -F $':' '{t = $1; $1 = $2; $2 = t; print; }' OFS=$':' | sed 's/^/vim +/' | sed '/:/s// /' | sed '/:/s// : /'
}
in your .bashrc and then
grepn SEARCHTERM file1 file2 ...
results in
vim +123 file1 : xxxxxxSEARCHTERMxxxxxxxxxx
vim +234 file2 : xxxxxxSEARCHTERMxxxxxxxxxx
Now, you can open vim on the correspondending line (for example line 123) by simply copying
vim +123 file1
to your shell.

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