I have a value stored in a file named cutoff1
If I cat cutoff1 it will look like
0.34722
I want to use the value stored in cutoff1 inside an awk script. Something like following
awk '{ if ($1 >= 'cat cutoff1' print $1 }' hist1.dat >hist_oc1.dat
I think I am making some mistakes. If I do manually it will look like
awk '{ if ($1 >= 0.34722) print $1 }' hist1.dat >hist_oc1.dat
How can I use the value stored in cutoff1 file inside the above mentioned awk script?
The easiest ways to achieve this are
awk -v cutoff="$(cat cutoff1)" '($1 >= cutoff){print $1}' hist.dat
awk -v cutoff="$(< cutoff1)" '($1 >= cutoff){print $1}' hist.dat
or
awk '(NR==FNR){cutoff=$1;next}($1 >= cutoff){print $1}' cutoff1 hist.dat
or
awk '($1 >= cutoff){print $1}' cutoff="$(cat cutoff1)" hist.dat
awk '($1 >= cutoff){print $1}' cutoff="$(< cutoff1)" hist.dat
note: thanks to Glenn Jackman to point to :
man bash Command substitution: Bash performs the expansion by executing command and replacing the command substitution with the
standard output of the command, with any trailing newlines deleted.
Embedded newlines are not deleted, but they may be removed during word
splitting. The command substitution $(cat file) can be replaced by
the equivalent but faster $(< file).
since awk can read multiple files just add the filename before your data file and treat first line specially. No need for external variable declaration.
awk 'NR==1{cutoff=$1; next} $1>=cutoff{print $1}' cutoff data
PS Just noticed that it's similar to the #kvantour's second answer, but keepin it here as a different flavor.
You could use getline to read a value from another file at your convenience. First the main file to process:
$ cat > file
wait
wait
did you see that
nothing more to see here
And cutoff:
$ cat cutoff
0.34722
An wwk script that reads a line from cutoff when it meets the string see in a record:
$ awk '/see/{if((getline val < "cutoff") > 0) print val}1' file
wait
wait
0.34722
did you see that
nothing more to see here
Explained:
$ awk '
/see/ { # when string see is in the line
if((getline val < "cutoff") > 0) # read a value from cutoff if there are any available
print val # and output the value from cutoff
}1' file # output records from file
As there was only one value, it was printed only once even see was seen twice.
Related
Please suggest how can I split the columns separated with ~|~ delimiter.(file: abc.dat)
a~|~1~|~x
b~|~1~|~y
c~|~2~|~z
I am trying below awk command but getting output 0 count.
awk -F'~|~' '$2 == 1' ${file} | wc -l
With your shown samples, please try following. We need not to use wc command along with awk, it could be done within awk itself.
awk -F'~\\|~' '$2 == 1{count++} END{print count}' "$file"
Explanation: Setting field separator as ~|~(escaped | here). Then checking if 2nd field is 1, increment variable count with 1 then. In END block of this program print its value.
For saving values into shell variable use like:
var=$(awk -F'~\\|~' '$2 == 1{count++} END{print count}' "$file")
You can also use ~[|]~ as FS value, as the pipe char used inside a bracket expression always matches itself, a pipe char:
counter=$(awk 'BEGIN{FS="~[|]~"} $2==1{cnt++} END{print cnt}' file)
See the online awk demo:
s='a~|~1~|~x
b~|~1~|~y
c~|~2~|~z'
counter=$(awk 'BEGIN{FS="~[|]~"} $2==1{cnt++} END{print cnt}' <<< "$s")
echo $counter
# => 2
I have spent hours trying to solve this. There are a bunch of answers as to how to prepend to all lines or specific lines but not with a variable text and a variable number.
while [ $FirstVariable -lt $NextVariable ]; do
#sed -i "$FirstVariables/.*/$FirstVariableText/" "$PWD/Inprocess/$InprocessFile"
cat "$PWD/Inprocess/$InprocessFile" | awk 'NR==${FirstVariable}{print "$FirstVariableText"}1' > "$PWD/Inprocess/Temp$InprocessFile"
FirstVariable=$[$FirstVariable+1]
done
Essentially I am looking for a particular string delimiter and then figuring out where the next one is and appending the first result back into the following lines... Note that I already figured out the logic I am just having issues prepending the line with the variables.
Example:
This >
Line1:
1
2
3
Line2:
1
2
3
Would turn into >
Line1:
Line1:1
Line1:2
Line1:3
Line2:
Line2:1
Line2:2
Line2:3
You can do all that using below awk one liner.
Assuming your pattern starts with Line, then the below script can be used.
> awk '{if ($1 ~ /Line/ ){var=$1;print $0;}else{ if ($1 !="")print var $1}}' $PWD/Inprocess/$InprocessFile
Line1:
Line1:1
Line1:2
Line1:3
Line2:
Line2:1
Line2:2
Line2:3
Here is how the above script works:
If the first record contains word Line then it is copied into an awk variable var. From next word onwards, if the record is not empty, the newly created var is appended to that record and prints it producing the desired result.
If you need to pass the variables dynamically from shell to awk you can use -v option. Like below:
awk -v var1=$FirstVariable -v var2=$FirstVariableText 'NR==var{print var2}1' > "$PWD/Inprocess/Temp$InprocessFile"
The way you addressed the problem is by parsing everything both with bash and awk to process the file. You make use of bash to extract a line, and then use awk to manipulate this one line. The whole thing can actually be done with a single awk script:
awk '/^Line/{str=$1; print; next}{print (NF ? str $0 : "")}' inputfile > outputfile
or
awk 'BEGIN{RS="";ORS="\n\n";FS=OFS="\n"}{gsub(FS,OFS $1)}1' inputfile > outputfile
Sometimes I want a bash script that's mostly a help file. There are probably better ways to do things, but sometimes I want to just have a file called "awk_help" that I run, and it dumps my awk notes to the terminal.
How can I do this easily?
Another idea, use #!/bin/cat -- this will literally answer the title of your question since the shebang line will be displayed as well.
Turns out it can be done as pretty much a one liner, thanks to #CharlesDuffy for the suggestions!
Just put the following at the top of the file, and you're done
cat "$BASH_SOURCE" | grep -v EZREMOVEHEADER
So for my awk_help example, it'd be:
cat "$BASH_SOURCE" | grep -v EZREMOVEHEADER
# Basic form of all awk commands
awk search pattern { program actions }
# advanced awk
awk 'BEGIN {init} search1 {actions} search2 {actions} END { final actions }' file
# awk boolean example for matching "(me OR you) OR (john AND ! doe)"
awk '( /me|you/ ) || (/john/ && ! /doe/ )' /path/to/file
# awk - print # of lines in file
awk 'END {print NR,"coins"}' coins.txt
# Sum up gold ounces in column 2, and find out value at $425/ounce
awk '/gold/ {ounces += $2} END {print "value = $" 425*ounces}' coins.txt
# Print the last column of each line in a file, using a comma (instead of space) as a field separator:
awk -F ',' '{print $NF}' filename
# Sum the values in the first column and pretty-print the values and then the total:
awk '{s+=$1; print $1} END {print "--------"; print s}' filename
# functions available
length($0) > 72, toupper,tolower
# count the # of times the word PASSED shows up in the file /tmp/out
cat /tmp/out | awk 'BEGIN {X=0} /PASSED/{X+=1; print $1 X}'
# awk regex operators
https://www.gnu.org/software/gawk/manual/html_node/Regexp-Operators.html
I found another solution that works on Mac/Linux and works exactly as one would hope.
Just use the following as your "shebang" line, and it'll output everything from line 2 on down:
test.sh
#!/usr/bin/tail -n+2
hi there
how are you
Running this gives you what you'd expect:
$ ./test.sh
hi there
how are you
and another possible solution - just use less, and that way your file will open in searchable gui
#!/usr/bin/less
and this way you can grep if for something too, e.g.
$ ./test.sh | grep something
I have a file that has multiple lines that starts with a keyword. I only want to modify one of them and it's easy to distinguish the two. I want the one that is under the [dbinfo] section. The domain name is static so I know that won't change.
awk -F '=' '$1 ~ /^dbhost/ {print $NF};' myfile.txt
myfile.txt
[ual]
path=/web/
dbhost=ez098sf
[dbinfo]
dbhost=ec0001.us-east-1.localdomain
dbname=ez098sf_default
dbpass=XXXXXX
You can use this awk command to first check for presence of [dbinfo] section and then modify dbhost parameter:
awk -v h='newhost' 'BEGIN{FS=OFS="="}
$0 == "[dbinfo]" {sec=1} sec && $1 == "dbhost"{$2 = h; sec=0} 1' file
[ual]
path=/web/
dbhost=ez098sf
[dbinfo]
dbhost=newhost
dbname=ez098sf_default
dbpass=XXXXXX
You want to utilize a little bit of a state machine here:
awk -F '=' '
$0 ~ /^\[.*\]/ {in_db_info=($0=="[dbinfo]"}
$0 ~ /^dbhost/{if (in_db_info) print $2;}' myfile.txt
You can also do it with sed:
sed '/\[dbinfo\]/,/\[/s/\(^dbhost=\).*/\1domain.com/' myfile.txt
I have a situation in awk where I need to convert an input format into another format and later use the number of records processed separately. Is there any way I can use a shell variable to get the value of NR in the END section? Something like:
cat file1 | awk 'some processing END{SHELL_VARIABLE=NR}' > file2
Then later use SHELL_VARIABLE outside awk.
I do not want to process the file and then do a wc -l separately as the files are huge.
One way: Use the redirection inside your awk command and print your result in the END block. And use command substitution to read the result in a shell variable:
my_var=$(awk '{ some processing; print "your output" >>file2 } END { print NR }' file1)
No subprocess can affect the parent's environment variables. What you can do is have awk write output to the file directly, then have it print the value you want to stdout and capture it. Or if you prefer, you could reverse that and have awk just print it to a file and read it back afterwards.
Incidentally, you have a UUOC.
rows=$(awk '{ ...; print > "file2"} END {print NR}' file1)
Or
awk '... END{print NR > "rows"}' file1 >file2
rows=$(<rows)
rm rows