{"id":622,"date":"2014-02-16T19:58:40","date_gmt":"2014-02-16T13:58:40","guid":{"rendered":"http:\/\/alexeyka.zantsev.com\/?p=622"},"modified":"2014-08-29T11:48:57","modified_gmt":"2014-08-29T05:48:57","slug":"awk","status":"publish","type":"post","link":"https:\/\/alexeyka.zantsev.com\/?p=622","title":{"rendered":"awk"},"content":{"rendered":"

Print the first line:
\ncat somefile.txt | awk ‘{print $1}’<\/samp><\/p>\n

… and see the number of active calls on Asterisk PBX:<\/p>\n

\r\nasterisk -rx 'core show calls' | head -n 1 | awk '{print $1}'\r\n<\/pre>\n
Print all but first 6 columns of the file:
\ncat somefile.txt | awk ‘{$1=$2=$3=$4=$5=$6=””; print $0}’<\/samp><\/p>\n
… and see who’s trying to connect to 5060\/TCP and 22\/TCP (some fields reduced):<\/p>\n
\r\nroot@vds:~# tail -n 2 \/var\/log\/syslog | awk '{$1=$2=$3=$4=$5=$6=\"\"; print $0}'\r\n      iptables denied Asterisk IN=eth0 SRC=69.60.119.204 DST=XX.XX.YY.ZZ PROTO=UDP SPT=5072 DPT=5060\r\n      iptables denied SSH IN=eth0 SRC=222.186.62.39 DST=XX.XX.YY.ZZ PROTO=TCP SPT=6000 DPT=22\r\n<\/pre>\n
By default, awk doesn’t separate columns. To do that, use comma:<\/p>\n
\r\nroot@vds:~# grep Aster \/var\/log\/syslog | awk '{print $1,$2,$3,$9,$13}'\r\nFeb 17 07:03:25 Asterisk SRC=74.118.193.77\r\nFeb 17 07:13:23 Asterisk SRC=85.25.194.185\r\nFeb 17 07:56:31 Asterisk SRC=188.138.34.254\r\nFeb 17 08:12:02 Asterisk SRC=200.12.49.147\r\n<\/pre>\n
PS: all these IPs are bad guys. They’re trying to connect to my SSH and SIP ports. So, I do not hide their addresses :)<\/p>\n
Update:<\/p>\n
In case you’ve got an output like<\/p>\n
“123456”
\n“234567”
\n“345678”<\/p>\n
and want to get rid of first and last symbols:<\/p>\n
rev input_file.txt | cut -c2- | rev | cut -c2-<\/pre>\n
In  case your columns have some other delimiters than space, p.e. comma, specify it:<\/p>\n
cat file.txt | awk -F',' '{print $3}'<\/pre>\n","protected":false},"excerpt":{"rendered":"
Print the first line: cat somefile.txt | awk ‘{print $1}’ … and see the number of active calls on Asterisk PBX: asterisk -rx ‘core show calls’ | head -n 1 | awk ‘{print $1}’ Print all but first 6 columns of the file: cat somefile.txt | awk ‘{$1=$2=$3=$4=$5=$6=””; print $0}’ … and see who’s trying […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[163],"class_list":["post-622","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-awk"],"_links":{"self":[{"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=\/wp\/v2\/posts\/622","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=622"}],"version-history":[{"count":10,"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=\/wp\/v2\/posts\/622\/revisions"}],"predecessor-version":[{"id":738,"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=\/wp\/v2\/posts\/622\/revisions\/738"}],"wp:attachment":[{"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=622"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=622"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/alexeyka.zantsev.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=622"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}