I have a path ./test/test1 and I need to extract the test1 part.
I can do that with
cut -d '/' -f 3
But I may also have a path like ./test/test1/test1a in which case I need to extract the test1a part.
I can do this in a similar manner by switching 2, 3, 4 to suit my needs.
But how can I achieve this if I have a list which contains some paths.
./test/test1
./test/test1/test1a/
./test/test1/test1a/example
How can I always make sure I extract the last part of the string after the last / delimiter? How do I start cutting from the last string up till the delimiter?
EDIT: Expected output:
test1
test1a
example
You can easily cut after the last delimiter, using awk, as you can see here:
cat conf.conf.txt | awk -F "/" '{ print $NF}'
(For your information: NF in awk stands for "Number of Fields".)
However, as the second line ends with a slash, the second result will be empty, as you see here:
test1
example
Is that what you want?
path=./foo/bar/baz
basename "$path"
# or pure shell:
echo "${path##*/}"
Both return baz. The counterpart, dirname, returns ./foo/bar.
It's not entirely clear what you mean by a "list". Perhaps you have the paths in an array, or just a space separated string. In either case, you can use basename, but the way you will use it depends on the data. If you have a space separated string, you can just use:
$ cat a.sh
#!/bin/sh
list='./test/test1
./test/test1/test1a/
./test/test1/test1a/example'
basename -a $list
$ ./a.sh
test1
test1a
example
That form will fail if there are characters in IFS in any of the names. If you have the names in an array, it is slightly easier to deal with that issue:
#!/bin/sh
list=('./test/with space/test1'
./test/test1/test1a/
./test/test1/test1a/example)
basename -a "${list[#]}"
Clean one-liner solution :
<<<"${test2}" mawk -F/ '$!_=$-_=$(NF-=_==$NF)'
test1
test1a
example
Tested and confirmed working on mawk-1.3.4, mawk 1.996, macos nawk, and gawk 5.1.1,
including invocation flags of -c/-P/-t/-S
—- The 4Chan Teller
Related
I am trying to write a loop with which I want to extract text file names in all sub-directories and append certain strings to it. Additionally, I want the text file name sorted for numbers after ^.
For example, I have three sub directories mydir1, mydir2, mydir3. I have,
in mydir1,
file223^1.txt
file221^2.txt
file666^3.txt
in mydir2,
file111^1.txt
file4^2.txt
In mydir3,
file1^4.txt
file5^5.txt
The expected result final.csv:
STRINGmydir1file223^1
STRINGmydir1file221^2
STRINGmydir1file666^3
STRINGmydir2file111^1
STRINGmydir2file4^2
STRINGmydir3file1^4
STRINGmydir3file5^5
This is the code I tried:
for dir in my*/; do
array=(${dir}/*.txt)
IFS=$'\n' RGBASE=($(sort <<<"${array[#]}"));
for RG in ${RGBASE[#]}; do
RGTAG=$(basename ${RG/.txt//})
echo "STRING${dir}${RGTAG}" >> final.csv
done
done
Can someone please explain what is wrong with my code? Also, there could be other better ways to do this, but I want to use the for-loop.
The output with this code:
$ cat final.csv
STRINGdir1file666^3.txt
STRINGdir2file4^2.txt
STRINGdir3file5^5.txt
As a starting point which works for your special case, I got a two liner for this.
mapfile -t array < <( find my* -name "*.txt" -printf "STRING^^%H^^%f\n" | cut -d"." -f1 | LANG=C sort -t"^" -k3,3 -k6 )
printf "%s\n" "${array[#]//^^/}"
To restrict the directory depth, you can add -maxdepth with the number of subdirs to search. The find command can also use regex in the search, which is applied to the whole path, which can be used to work on a more complex directory-tree.
The difficulty was the sort on two positions and the delimiter.
My idea was to add a delimiter, which easily can be removed afterwards.
The sort command can only handle one delimiter, therefore I had to use the double hat as delimiter which can be removed without removing the single hat in the filename.
A solution using decorate-sort-undecorate idiom could be:
printf "%s\n" my*/*.txt |
sed -E 's_(.*)/(.*)\^([0-9]+).*_\1\t\3\tSTRING\1\2^\3_' |
sort -t$'\t' -k1,1 -k2,2n |
cut -f3
assuming filenames don't contain tab or newline characters.
A basic explanation: The printf prints each pathname on a separate line. The sed converts the pathname dir/file^number.txt into dir\tnumber\tSTRINGdirfile^number (\t represents a tab character). The aim is to use the tab character as a field separator in the sort command. The sort sorts the lines by the first (lexicographically) and second fields (numerically). The cut discards the first and second fields; the remaining field is what we want.
I have the following format for filenames: filename_1234.svg
How can I retrieve the numbers preceded by an underscore and followed by a dot. There can be between one to four numbers before the .svg
I have tried:
width=${fileName//[^0-9]/}
but if the fileName contains a number as well, it will return all numbers in the filename, e.g.
file6name_1234.svg
I found solutions for two underscores (and splitting it into an array), but I am looking for a way to check for the underscore as well as the dot.
You can use simple parameter expansion with substring removal to simply trim from the right up to, and including, the '.', then trim from the left up to, and including, the '_', leaving the number you desire, e.g.
$ width=filename_1234.svg; val="${width%.*}"; val="${val##*_}"; echo $val
1234
note: # trims from left to first-occurrence while ## trims to last-occurrence. % and %% work the same way from the right.
Explained:
width=filename_1234.svg - width holds your filename
val="${width%.*}" - val holds filename_1234
val="${val##*_}" - finally val holds 1234
Of course, there is no need to use a temporary value like val if your intent is that width should hold the width. I just used a temp to protect against changing the original contents of width. If you want the resulting number in width, just replace val with width everywhere above and operate directly on width.
note 2: using shell capabilities like parameter expansion prevents creating a separate subshell and spawning a separate process that occurs when using a utility like sed, grep or awk (or anything that isn't part of the shell for that matter).
Try the following code :
filename="filename_6_1234.svg"
if [[ "$filename" =~ ^(.*)_([^.]*)\..*$ ]];
then
echo "${BASH_REMATCH[0]}" #will display 'filename_6_1234.svg'
echo "${BASH_REMATCH[1]}" #will display 'filename_6'
echo "${BASH_REMATCH[2]}" #will display '1234'
fi
Explanation :
=~ : bash operator for regex comparison
^(.*)_([^.])\..*$ : we look for any character, followed by an underscore, followed by any character, followed by a dot and an extension. We create 2 capture groups, one for before the last underscore, one for after
BASH_REMATCH : array containing the captured groups
Some more way
[akshay#localhost tmp]$ filename=file1b2aname_1234.svg
[akshay#localhost tmp]$ after=${filename##*_}
[akshay#localhost tmp]$ echo ${after//[^0-9]}
1234
Using awk
[akshay#localhost tmp]$ awk -F'[_.]' '{print $2}' <<< "$filename"
1234
I would use
sed 's!_! !g' | awk '{print "_" $NF}'
to get from filename_1234.svg to _1234.svg then
sed 's!svg!!g'
to get rid of the extension.
If you set IFS, you can use Bash's build-in read.
This splits the filename by underscores and dots and stores the result in the array a.
IFS='_.' read -a a <<<'file1b2aname_1234.svg'
And this takes the second last element from the array.
echo ${a[-2]}
There's a solution using cut:
name="file6name_1234.svg"
num=$(echo "$name" | cut -d '_' -f 2 | cut -d '.' -f 1)
echo "$num"
-d is for specifying a delimiter.
-f refers to the desired field.
I don't know anything about performance but it's simple to understand and simple to maintain.
in a text file I have the following entries:
10.1.0.10-15
10.1.0.20-25
10.1.0.30-35
10.1.0.40-45
I would like to print 10.1.0.10,15, 20, 25,30
cat file | grep 10.1.0.[1,2,3][0.5] -- prints 10,15,20,25,30, 35.
How do I suppress 35?
I do not want to use grep -v .35 ...just want to print specific IPs or #s.
You can use:
grep -E '10\.1\.0\.([12][05]|30)' file
However awk will be more readable:
awk -F '[.-]' '$4%5 == 0 && $4 >= 10 && $4 <= 30' file
10.1.0.10-15
10.1.0.20-25
10.1.0.30-35
Note that the , and . in the character classes are not needed — in fact, they match data that you don't want the pattern to match. Also, the . outside the character classes match any character (digit, letter, or . as you intend) — you need to escape them with a backslash so that they only match an actual ..
Also, you are making Useless Use of cat (UUoC) errors; grep can perfectly well read from a file.
As to what to do, probably use:
grep -E '10\.1\.0\.([12][05]|30)' file
This uses the extended regular expressions (formerly for egrep, now grep -E). It also avoids the dots from matching any character.
I'm not sure if what you want is just printing the first two IPs, excluding that one with 35. In that case cat file | grep '10.1.0.[1-3]0.[15|25]' does the job.
Remember that you can use conditional expressions such as | to help you.
Okay so what I am trying to figure out is how do I count the number of periods in a string and then cut everything up to that point but minus 2. Meaning like this:
string="aaa.bbb.ccc.ddd.google.com"
number_of_periods="5"
number_of_periods=`expr $number_of_periods-2`
string=`echo $string | cut -d"." -f$number_of_periods`
echo $string
result: "aaa.bbb.ccc.ddd"
The way that I was thinking of doing it was sending the string to a text file and then just greping for the number of times like this:
grep -c "." infile
The reason I don't want to do that is because I want to avoid creating another text file for I do not have permission to do so. It would also be simpler for the code I am trying to build right now.
EDIT
I don't think I made it clear but I want to make finding the number of periods more dynamic because the address I will be looking at will change as the script moves forward.
If you don't need to count the dots, but just remove the penultimate dot and everything afterwards, you can use Bash's built-in string manuipulation.
${string%substring}
Deletes shortest match of $substring from back of $string.
Example:
$ string="aaa.bbb.ccc.ddd.google.com"
$ echo ${string%.*.*}
aaa.bbb.ccc.ddd
Nice and simple and no need for sed, awk or cut!
What about this:
echo "aaa.bbb.ccc.ddd.google.com"|awk 'BEGIN{FS=OFS="."}{NF=NF-2}1'
(further shortened by helpful comment from #steve)
gives:
aaa.bbb.ccc.ddd
The awk command:
awk 'BEGIN{FS=OFS="."}{NF=NF-2}1'
works by separating the input line into fields (FS) by ., then joining them as output (OFS) with ., but the number of fields (NF) has been reduced by 2. The final 1 in the command is responsible for the print.
This will reduce a given input line by eliminating the last two period separated items.
This approach is "shell-agnostic" :)
Perhaps this will help:
#!/bin/sh
input="aaa.bbb.ccc.ddd.google.com"
number_of_fields=$(echo $input | tr "." "\n" | wc -l)
interesting_fields=$(($number_of_fields-2))
echo $input | cut -d. -f-${interesting_fields}
grep -o "\." <<<"aaa.bbb.ccc.ddd.google.com" | wc -l
5
I have a text file with the following structure:
text1;text2;text3;text4
...
I need to write a script that gets 2 arguments: the column we want to search in and the content we want to find.
So the script should output only the lines (WHOLE LINES!) that match content(arg2) found in column x(arg1).
I tried with egrep and sed, but I'm not experienced enough to finish it. I would appreciate some guidance...
Given your added information of needing to output the entire line, awk is easiest:
awk -F';' -v col=$col -v pat="$val" '$col ~ pat' $input
Explaining the above, the -v options set awk variables without needing to worry about quoting issues in the body of the awk script. Pre-POSIX versions of awk won't understand the -v option, but will recognize the variable assignment without it. The -F option sets the field separator. In the body, we are using a pattern with the default action (which is print); the pattern uses the variables we set with -v for both the column ($ there is awk's "field index" operator, not a shell variable) and the pattern (and pat can indeed hold an awk-style regex).
cat text_file.txt| cut -d';' column_num | grep pattern
It prints only the column that is matched and not the entire line. let me think if there is a simple solution for that.
Python
#!/usr/bin/env python
import sys
column = 1 # the column to search
value = "the data you're looking for"
with open("your file","r") as source:
for line in source:
fields = line.strip().split(';')
if fields[column] == value:
print line
There's also a solution with egrep. It's not a very beautiful one but it works:
egrep "^([^;]+;){`expr $col - 1`}$value;([^;]+;){`expr 3 - $col`}([^;]+){`expr 4 - $col`}$" filename
or even shorter:
egrep "^([^;]+;){`expr $col - 1`}$value(;|$)" filename
grep -B1 -i "string from previous line" |grep -iv 'check string from previous line' |awk -F" " '{print $1}'
This will print your line.