Bash : how to grep string from file

Question

am having issue with grep as VESTACP is using it a lot.

i have file mysql.conf

HOST='localhost' USER='root' PASSWORD='xxxxxx' CHARSETS='UTF8,LATIN1,WIN1250,WIN1251,WIN1252,WIN1256,WIN1258,KOI8' MAX_DB='500' U_SYS_USERS='' U_DB_BASES='1' SUSPENDED='no' TIME='05:32:47' DATE='2016-03-20'

now when i run

 echo host_str=$(grep "HOST='$1'" $VESTA/conf/mysql.conf)

i get empty result , although there is HOST in mysql.conf file which i pasted above in code

so any idea whats wrong with it

UPDATE :: Vesta db connect code block

host_str=$(grep "HOST='$1'" $VESTA/conf/mysql.conf)
eval $host_str
if [ -z $HOST ] || [ -z $USER ] || [ -z $PASSWORD ]; then
    echo "Error: mysql config parsing failed"
    log_event "$E_PARSING" "$EVENT"
    exit $E_PARSING
fi

and i get

Error: mysql config parsing failed

Are you running this in a script? What do you want to do exactly? — Julien Lopez
– Julien Lopez, Commented Mar 25, 2016 at 14:32
Well if $1 is empty then you are effectively running grep "HOST=''" $VESTA/conf/mysql.conf command — anubhava
– anubhava, Commented Mar 25, 2016 at 14:46
thats strange $1 should contain localhost . as you can see in file its localhost — user889030
– user889030, Commented Mar 25, 2016 at 14:47

Julien Lopez · Accepted Answer · 2016-03-25 14:59:46Z

1

$1 is the first parameter of your script.

So, host_str=$(grep "HOST='$1'" $VESTA/conf/mysql.conf) gets the line containing some variables from your file according to your parameter, and eval $host_str sets these variables in your script.

Therefore, your script needs an argument to know which host to look for in your file, in your case, it's localhost, so run: ./yourscript.sh localhost.

answered Mar 25, 2016 at 14:59

Julien Lopez

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Comments

Harald · Accepted Answer · 2016-03-25 14:31:30Z

1

You probably don't want to use $1. Rather try this:

echo host_str=$(grep -o "HOST='[^']*'" $VESTA/conf/mysql.conf)

The [^']* expands to everything that happens to be in between the single quotes. The option -o makes sure you only get the matching string, not the whole line, if that is what you want.

answered Mar 25, 2016 at 14:31

Harald

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3 Comments

Jonathan Leffler Over a year ago

@Aaron: Que? The only version of grep that doesn't consider the pattern as a regex is fgrep, aka grep -F these days. Adding -E makes grep run in egrep mode — with extended regular expressions instead of basic regular expressions.

user889030 Over a year ago

vestacp need $1 for further operations

Harald Over a year ago

Well, but if you keep $1 in the pattern and if it does not expand exactly to what is in the file, your match result will stay empty.

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