#!/usr/bin/expect -f
set name [lindex $argv 0]
send "grep $name /usr/local/bin/c | awk '{print $3}' | awk '{print substr($1,10)}'\r"
spawn grep $name /usr/local/bin/c | awk '{print $3}' | awk '{print substr($1,10)}'
I have tried "\" escaping quotes and special symbols. It doesn't work. I also have tried to send and spawn. Doesn't work. If I run just the grep........... command on the line it returns what I need. Any help on how to get this to run from my expect file would be great. Thanks.
Single quotes have no special meaning in expect. Use braces instead for the same effect:
spawn awk -v n="perferx" {$0 ~ n {print substr($3,10,5)}} /usr/local/bin/c
# .......................^..............................^
Ref: Tcl syntax rules, #6
No substitutions are performed on the characters between the braces
Additionally, without seeing what you're doing with the output, perhaps you don't need spawn
set output [exec awk -v n="perferx" {$0 ~ n {print substr($3,10,5)}} /usr/local/bin/c]
Now, you can do simple string parsing on $output
Related
I am trying to capture the last line of a file as a variable for use in an awk command.
Here is an example of the file (the end of it) :
cat file.txt
....
phylum:Chlorophyta 1
phylum:Mucoromycota 1
column 6:
superkingdom:Eukaryota 99
column 7:
99
I want to use that '99' as an integer in an awk command, saving it as a variable,
tail -n1 file.txt
99
e.g.
div=$(tail -n1 file.txt)
echo $div
99
To be used in a 2nd file (conf.txt), to divide the numbers in the 2nd field:
cat conf.txt
Class 88
Family 78
Genus 44
Species 23
BUT, when I try to use the $div variable in the awk command (using -v flag as suggested here and elsewhere with awk when taking a variable) I get this error:
awk -v a=$div '{print $2/a}' conf.txt
awk: can't open file {print $2/a}
source line number 1
But when saivng 99 as a variable simply on the cmd line, It works just fine:
num=99
awk -v a=$num '{print $2/a}' conf.txt
0.888889
0.787879
0.444444
0.232323
Are there extra spaces/characters in the capture from tail -1? I am missing something simple, but fundamental.
Ultimatey, I don't even want to have to save as a separate variable first If I dont have to, instead, just capture that last line number (99) and put directly into an awk cmd, e.g.:
awk '{print $2/[tail -1 file.txt]}' conf.txt
This is psuedo code (in the brackets) ...but, this would ultimately be what Id want...
Thanks for any help!
There's a space at the beginning of the last line, so the command is becoming
awk -v a= 99 '{print $2/a}' conf.txt
This is setting a to an empty string, treating 99 as the awk script, and the rest as filenames.
Remove the spaces from $div.
div=${div// /}
Use quotes as a habit in the shell.
Given:
cat file
blah blah
99
The command n=$(tail -n1 file) produces leading spaces in front of the 99:
n=$(tail -n1 file)
printf "\"%s\"\n" "$n"
" 99"
It is especially a bug that bites when you think you are checking the value of $n without quotes because the leading spaces are stripped by the shell prior to invoking echo.
Consider:
echo $n # no quotes - leading spaces stripped
99
echo "$n" # preserve whitespace...
99
Now if you try and pass that argument without quotes to awk, the space has meaning to the shell and screws up how the command is interpreted:
awk -v n=$n 'BEGIN{printf "\"%s\", %s\n", n, n+1}'
awk: fatal: cannot open file `BEGIN{printf "\"%s\", %s\n", n, n+1}' for reading: No such file or directory
vs:
awk -v n="$n" 'BEGIN{printf "\"%s\", %s\n", n, n+1}'
" 99", 100
If you want to use awk to replace the use of tail you use the idiom of FNR==NR to test if the file is the first file and $1==$1+0 to test if awk is interpreting what it sees as a number:
awk 'FNR==NR {n=$1+0==$1 ? $1+0 : n; next} # n ends up being the last number seen
$2==$2+0{print $2/n}
' file conf.txt
0.888889
0.787879
0.444444
0.232323
Rather than have shell call some command to get the last line of file.txt then save it in a shell variable, then set an awk variable to that same value populated from the shell variable and passing it to awk, just use one call to awk:
$ awk 'NR==FNR{n=$1; next} {print $2/n}' file.txt conf.txt
0.888889
0.787879
0.444444
0.232323
Enabling debug mode and running the awk command:
$ set -x
$ awk -v a=$div '{print $2/a}' conf.txt
+ awk -v a= 99 '{print $2/a}'
awk: fatal: cannot open file `{print $2/a}' for reading: No such file or directory
Of interest:
-v a= - define awk variable a as being empty
99 - awk code/script
'{print $2/a}' - first file passed to awk script, and the source of the error message
As others have pointed out you can get around the error by wrapping $div in double quotes:
$ awk -v a="$div" '{print $2/a}' conf.txt
+ awk -v 'a= 99' '{print $2/a}' conf.txt
0.888889
0.787879
0.444444
0.232323
Of interest:
-v '= 99' - define awk variable a and string ' 99'
in this case awk ignores the spaces when the rest of the variable can be interpreted as a numeric
'{print $2/a}' - awk code/script
conf.txt - file passed to awk script
Barmar and dawg have addressed stripping the blanks from div and using awk for the entire process, respectively.
I'm trying different commands to process csv file where the separator is the pipe | character.
While those commands do work when the comma is a separator, it throws an error when I replace it with the pipe:
awk -F[|] "NR==FNR{a[$2]=$0;next}$2 in a{ print a[$2] [|] $4 [|] $5 }" OFS=[|] file1.csv file2.csv
awk "{print NR "|" $0}" file1.csv
I tried, "|", [|], /| to no avail.
I'm using Gawk on windows. What I'm I missing?
You tried "|", [|] and /|. /| does not work because the escape character is \, whereas [] is used to define a range of fields, for example [,-] if you want FS to be either , or -.
To make it work "|" is fine, are you sure you used it this way? Alternativelly, escape it --> \|:
$ echo "he|llo|how are|you" | awk -F"|" '{print $1}'
he
$ echo "he|llo|how are|you" | awk -F\| '{print $1}'
he
$ echo "he|llo|how are|you" | awk 'BEGIN{FS="|"} {print $1}'
he
But then note that when you say:
print a[$2] [|] $4 [|] $5
so you are not using any delimiter at all. As you already defined OFS, do:
print a[$2], $4, $5
Example:
$ cat a
he|llo|how are|you
$ awk 'BEGIN {FS=OFS="|"} {print $1, $3}' a
he|how are
For anyone finding this years later: ALWAYS QUOTE SHELL METACHARACTERS!
I think gawk (GNU awk) treats | specially, so it should be quoted (for awk). OP had this right with [|]. However [|] is also a shell pattern. Which in bash at least, will only expand if it matches a file in the current working directory:
$ cd /tmp
$ echo -F[|] # Same command
-F[|]
$ touch -- '-F|'
$ echo -F[|] # Different output
-F|
$ echo '-F[|]' # Good quoting
-F[|] # Consistent output
So it should be:
awk '-F[|]'
# or
awk -F '[|]'
awk -F "[|]" would also work, but IMO, only use soft quotes (") when you have something to actually expand (or the string itself contains hard quotes ('), which can't be nested in any way).
Note that the same thing happens if these characters are inside unquoted variables.
If text or a variable contains, or may contain: []?*, quote it, or set -f to turn off pathname expansion (a single, unmatched square bracket is technically OK, I think).
If a variable contains, or may contain an IFS character (space, tab, new line, by default), quote it (unless you want it to be split). Or export IFS= first (bearing the consequences), if quoting is impossible (eg. a crazy eval).
Note: raw text is always split by white space, regardless of IFS.
Try to escape the |
echo "more|data" | awk -F\| '{print $1}'
more
You can escape the | as \|
$ cat test
hello|world
$ awk -F\| '{print $1, $2}' test
hello world
I'm trying to do something pretty simple but its appears more complicated than expected...
I've lines in a text file, separated by the comma and that I want to output to another file, without the first field.
Input:
echo file1,item, 12345678 | awk -F',' '{OFS = ";";$1=""; print $0}'
Output:
;item; 12345678
As you can see the spaces before 12345678 are kind of merged into one space only.
I also tried with the cut command:
echo file1,item, 12345678 | cut -d, -f2-
and I ended up with the same result.
Is there any workaround to handle this?
Actually my entire script is as follows:
cat myfile | while read l_line
do
l_line="'$l_line'"
v_OutputFile=$(echo $l_line | awk -F',' '{print $1}')
echo $(echo $l_line | cut -d, -f2-) >> ${v_OutputFile}
done
But stills in l_line all spaces but one are removed. I also created the quotes inside the file but same result.
it has nothing to do with awk. quote the string in your echo:
#with quotes
kent$ echo 'a,b, c'|awk -F, -v OFS=";" '{$1="";print $0}'
;b; c
#without quotes
kent$ echo a,b, c|awk -F, -v OFS=";" '{$1="";print $0}'
;b; c
The problem is with your invocation of the echo command you're using to feed awk the test data above. The shell is looking at this command:
echo file1,item, 12345678
and treating file1,item, and 12345678 as two separate parameters to echo. echo just prints all its parameters, separated by one space.
If you were to quote the whitespace, as follows:
echo 'file1,item, 12345678'
the shell would interpret this as a single parameter to feed to echo, so you'd get the expected result.
Update after edit to OP - having seen your full script, you could do this entirely in awk:
awk -F, '{ OFS = "," ; f = $1 ; sub("^[^,]*,","") ; print $0 >> f }' myfile
I try searching a file by using awk. How can I ask awk to read a variable from the command line as a name to get searched in the file:
this is a regular way I use to search the file and I can ask the user to enter a name to search in the file.txt
awk -f myAwk.awk file.txt
How can I manage it like this :
awk -f myAwk.awk file.txt nameToSearch
How can I use ARGC and ARGV to search the nameToSearch in the file.txt?
What you're probably looking for is
awk [-W option] [-F value] [-v var=value] [--] 'program text' [file ...]
so
awk -v MYVAR=nameToSearch -v OTHERVAR=somethingElse -f myAwk.awk file.txt
Is that it? of course order of switches ( -f, -v ) does not matter. Obvously you then need to include MYVAR ( OTHERVAR ) for a variable identifier inside awk program itself.
To pass a variable to awk, you can use the -v command.
For example:
cat file.txt | awk -v p="stringToSearch" '$0 ~ p'
In this command, tou replace stringToSearch with a pattern (please keep the double quote, they are useful for preserving spaces). The awk command $0 ~ p compares the current line to the given pattern.
Another approach is to build the awk command from the shell:
p="stringToSearch"
awk "/$p/" file.txt
You must use double quotes in the command to force expanding $p.
If it's permitted to change the order of arguments, so that we can do this:
awk -f myAwk.awk nameToSearch file.txt
then you can do:
awk 'NR==1 { nameToSearch = $0; next} { ... rest of myAwk.awk here ...}' nameToSearch file.txt
You can of course add the NR==1 {...} block to the beginning of your myAwk.awk file, then continue using:
awk -f myAwk.awk nameToSearch file.txt
The technique Piotr Wadas describes has the same effect:
awk -v nameToSearch=whatever -f myAwk.awk file.txt
and that's what I'd use myself, rather than passing whatever as an additional argument to the script. Passing whatever as an additional argument is what scripters had to do before the -v facilities were added to awk. If writing -v nameToSearch= is too verbose, then I'd wrap the whole thing up in a shell script, and say:
myShellScript whatever file.txt
But you asked how to do it by passing whatever as an additional argument to the awk script, so that's what I demonstrated.
I'm tweaking a KSH script and I'm trying to ssh into various hosts and execute a grep command on vfstab that will return a certain line. The problem is, I can't get the following to work below. I'm trying to get the line it returns and append it to a destination file. Is there a better way to do this, ex assign the grep statement to a command variable? The command works fine within the script, but the nested quotations seems to bugger it. Anyways, here's the line:
ssh $user#$host "grep '/var/corefiles' $VFSTAB_LOC | awk '{print $3, $7}' " >> $DEST
This results in:
awk: syntax error near line 1
awk: illegal statement near line one
If there is a better/more correct way to do this please let me know!
You're putting the remote command in double quotes, so the $3 and $7 in the awk body will be substituted. awk probably sees '{print ,}'. Escape the dollar signs in the awk body.
ssh $user#$host "grep '/var/corefiles' $VFSTAB_LOC | awk '{print \$3, \$7}' " >> $DEST
^ ^
I tried below and it worked for me (in ksh) not sure why it would error out in your case
user="username";
host="somehost";
VFSTAB_LOC="result.out";
DEST="/home/username/aaa.out";
echo $DEST;
`ssh $user#$host "grep '/abc/dyf' $VFSTAB_LOC | awk '{print $3, $1}'" >> $DEST`;