tab="`\echo '\t'`"
grep "^.*${tab}.*${tab}.*${tab}.*${tab}.*${tab}" $file |
grep -vi ssm_id |
cut -f 1,5,6 -d "${tab}" > $rmloadfile
I am getting error as
-cut: invalid delimiter
the above code is part of my bash script.
Ignoring the actual problem, you really want to use awk here instead of this combination of grep and cut:
awk 'NF>=6 && tolower($0) !~ ssm_id { print $1, $5, $6 }' $file > $rmloadfile
The echo command doesn't interpret backslash escaped characters by default. It has to be enabled using the -e switch.
If you use:
tab="$(echo -e '\t')"
it works.
But I'd rather recommend using the approach proposed by #devnull in the comments, or refer to the linked question.
Related
I run the command
df -gP /data1 /data2 | grep -v File | awk '{print $1}' |
awk -F/dev/ '$0=$2' | tr '\n' '
on the AIX shell (ksh) and it prints the output below:
lv_data01 lv_data02 root#testhost:/
However, I would like the output to be printed this way. Could someone help?
lv_data01 lv_data02
Using grep … | awk … | awk … is not necessary; a single awk could do the whole job. So could sed and it might even be easier. I'd be tempted to deal with the spacing by using:
x=$(df … | sed …); echo $x
The tr command, once corrected, replaces newlines with spaces, so the prompt follows without a newline before it. The ; echo suggestion adds the missing newline; the echo $x suggestion (note no double quotes) does too.
As for the sed command:
sed -n '/File/!{ s/[[:space:]].*//; s%^.*/dev/%%p; }'
Don't print anything by default
If the line doesn't match File (doing the work of grep -v):
remove the first space (blank or tab) and everything after it (doing the work of awk '{print $1}')
replace everything up to /dev/ with nothing and print (doing the work of awk -F/dev/ '{$0=$2}')
The command substitution and capture, followed by echo, deals with spaces and newlines.
So, my suggested solution is:
x=$(df -gP /data1 /data2 | sed -n '/File/!{ s/[[:space:]].*//; s%^.*/dev/%%p; }'); echo $x
You could add unset x after the echo if you are going to be using this directly in the shell and not in a shell script. If it'll be encapsulated in a shell script, you don't have to worry about it.
I'm blithely assuming the output from df -gP won't contain a path such as this, with two occurrences of /dev:
/who/knows/dev/lv_data01/dev/bin
If that's a real problem, you can fix the sed script, but I don't think it will be. It's one thing the second awk script in the question handles differently.
i have a variable Firstline with value FHEAD,0000000001,STKU,20150927000000,201509270000000000,1153,,0000000801,W from which i need 5th field alone.
Can any one help me to resolve this.
I have used the below command but it is giving me an error
echo "FHEAD,0000000001,STKU,20150927000000,201509270000000000,1153,,0000000801,W" | awk -f ',' '{print $5}'
awk: fatal: can't open source file
,' for reading (No such file or directory)
As you tag it as bash and not awk (which is also a valid solution), you can do
IFS=, read -a a <<< "FHEAD,0000000001,STKU,20150927000000,201509270000000000,1153,,0000000801,W"
echo ${a[4]}
to obtain the same result without spawning a new process (note that bash arrays are 0-based).
Try -F not -f.
-F is for the field separator
-f is for the filename of the awk program.
You can use sed too
echo "..." | sed -E 's/([^,]*,){4}([^,]*).*/\2/'
How can I rewrite the following bash command to be ShellCheck compliant?
memory=$(cat /proc/meminfo | grep 'MemTotal:' | awk {'print $2}' 2> /dev/null)
It is currently complaining about:
Useless cat. Consider 'cmd < file | ..' or 'cmd file | ..'
This { is literal.
The shellcheck complaints are
Using cat filename | grep 'pattern' instead of grep 'pattern' filename
The first brace in the awk command is on the outside of the single quote, hence literal; it should be awk '{command}'
So, a version that would satisfy shellcheck would look like
memory=$(grep 'MemTotal:' /proc/meminfo | awk '{print $2}')
I'm not sure why you redirected standard error, so I dropped it.
However, piping grep output to awk is rarely the best solution; awk can do almost anything grep can, so you could further simplify to
memory=$(awk '/MemTotal:/ { print $2 }' /proc/meminfo)
No pipes!
Just as a guess, you probably want:
memory=$(grep 'MemTotal:' /proc/meminfo | awk '{print $2}' 2> /dev/null)
However, that's a direct interpretation of the shellcheck output, so I am unsure as to what you are asking about. As it stands, you are essentially asking: "Why isn't this working?".
I need to grep multiple strings, but i don't know the exact number of strings.
My code is :
s2=( $(echo $1 | awk -F"," '{ for (i=1; i<=NF ; i++) {print $i} }') )
for pattern in "${s2[#]}"; do
ssh -q host tail -f /some/path |
grep -w -i --line-buffered "$pattern" > some_file 2>/dev/null &
done
now, the code is not doing what it's supposed to do. For example if i run ./script s1,s2,s3,s4,.....
it prints all lines that contain s1,s2,s3....
The script is supposed to do something like grep "$s1" | grep "$s2" | grep "$s3" ....
grep doesn't have an option to match all of a set of patterns. So the best solution is to use another tool, such as awk (or your choice of scripting languages, but awk will work fine).
Note, however, that awk and grep have subtly different regular expression implementations. It's not clear from the question whether the target strings are literal strings or regular expression patterns, and if the latter, what the expectations are. However, since the argument comes delimited with commas, I'm assuming that the pieces are simple strings and should not be interpreted as patterns.
If you want the strings to be interpreted as patterns, you can change index to match in the following little program:
ssh -q host tail -f /some/path |
awk -v STRINGS="$1" -v IGNORECASE=1 \
'BEGIN{split(STRINGS,strings,/,/)}
{for(i in strings)if(!index($0,strings[i]))next}
{print;fflush()}'
Note:
IGNORECASE is only available in gnu awk; in (most) other implementations, it will do nothing. It seems that is what you want, based on the fact that you used -i in your grep invocation.
fflush() is also an extension, although it works with both gawk and mawk. In Posix awk, fflush requires an argument; if you were using Posix awk, you'd be better off printing to stderr.
You can use extended grep
egrep "$s1|$s2|$s3" fileName
If you don't know how many pattern you need to grep, but you have all of them in an array called s, you can use
egrep $(sed 's/ /|/g' <<< "${s[#]}") fileName
This creates a herestring with all elements of the array, sed replaces the field separator of bash (space) with | and if we feed that to egrep we grep all strings that are in the array s.
test.sh:
#!/bin/bash -x
a=" $#"
grep ${a// / -e } .bashrc
it works that way:
$ ./test.sh 1 2 3
+ a=' 1 2 3'
+ grep -e 1 -e 2 -e 3 .bashrc
(here is lots of text that fits all the arguments)
I'm trying to do some manipulation with Wordpress and I'm trying to write a script for it...
# cat /usr/local/uftwf/_wr.sh
#!/bin/sh
# $Id$
#
table_prefix=`grep ^\$table_prefix wp-config.php | awk -F\' '{print $2}'`
echo $table_prefix
#
Yet I'm getting following output
# /usr/local/uftwf/_wr.sh
ABSPATH ABSPATH wp-settings.php_KEY LOGGED_IN_KEY NONCE_KEY AUTH_SALT SECURE_AUTH_SALT LOGGED_IN_SALT NONCE_SALT wp_0zw2h5_ de_DE WPLANG WP_DEBUG s all, stop editing! Happy blogging. */
#
Running from command line, I get the correct output that I'm looking for:
# grep ^\$table_prefix wp-config.php | awk -F\' '{print $2}'
wp_0zw2h5_
#
What is going wrong in the script?
The problem is the grep command:
table_prefix=`grep ^\$table_prefix wp-config.php | awk -F\' '{print $2}'`
It either needs three backslashes - not one - or you need to use single quotes (which is much simpler):
table_prefix=$(grep '^$table_prefix' wp-config.php | awk -F"'" '{print $2}')
It's also worth using the $( ... ) notation in general.
The trouble is that the backquotes removes the backslash, so the shell variable is evaluated, and what's passed to grep is, most likely, just ^, and each line starts with a beginning of line.
This has all the appearance as though the grep is not omitting all the lines that are not matching, when you issue the echo $table_prefix without quotes it collapses all the white space into a single output line, if you issue an: echo "$table_prefix", you would see the match with all the other white-space that was output.
I'd recommend the following sed expression instead:
table_prefix=$(sed -n "s/^\$table_prefix.*'\([^']*\)'.*/\1/p" wp-config.php)
You should try
#!/bin/sh
table_prefix=$(awk -F"'" '/^\$table_prefix/{print $2}' wp-config.php)
echo $table_prefix
Does this one work for you?
awk -F\' '/^\$table_prefix/ {print $2}' wp-config.php
Update
If you are using shell scripting, there is no need to call up awk, grep:
#!/bin/sh
while read varName op varValue theRest
do
if [ "_$varName" = "_\$table_prefix" ]
then
table_prefix=${varValue//\'/} # Remove the single quotes
table_prefix=${table_prefix/;/} # Remove the semicolon
break
fi
done < wp-config.php
echo "Found: $table_prefix"