Just deleted tons of stale, unsused user accounts. Here are some KSH shell basics and special shell variable. I need to Google them up myself to get reminded that ‘$?’ is the output variable for script execution. That is, it’s 0 for successful execution and 1 if there is any error.<\/p>\n
<\/p>\n
Special shell variables
\nThere are some variables which are set internally by the shell and which are available to the user:<\/p>\n
Name Description
\n——————————————————————————–
\n$1 – $9 these variables are the positional parameters.<\/p>\n
$0 the name of the command currently being executed.<\/p>\n
$# the number of positional arguments given to this
\n invocation of the shell.<\/p>\n
$? the exit status of the last command executed is
\n given as a decimal string. When a command
\n completes successfully, it returns the exit status
\n of 0 (zero), otherwise it returns a non-zero exit
\n status.<\/p>\n
$$ the process number of this shell – useful for
\n including in filenames, to make them unique.<\/p>\n
$! the process id of the last command run in
\n the background.<\/p>\n
$- the current options supplied to this invocation
\n of the shell.<\/p>\n
$* a string containing all the arguments to the
\n shell, starting at $1.<\/p>\n
$@ same as above, except when quoted.<\/p>\n
Branching<\/strong> if then else fi ——————————————————————————–<\/p>\n Looping Command Syntax for Scripts<\/strong><\/p>\n http:\/\/www.well.ox.ac.uk\/~johnb\/comp\/unix\/ksh.html<\/p>\n Removing accounts from predefine list:<\/p>\n for each in `cat .\/list-a` done<\/code><\/p>\n Or course, the sleep there is just for aesthetic.. I want to see the screen<\/p>\n","protected":false},"excerpt":{"rendered":" Just deleted tons of stale, unsused user accounts. Here are some KSH shell basics and special shell variable. I need to Google them up myself to get reminded that ‘$?’ is the output variable for …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16,212,17,5,3],"tags":[340,341,342,343,29,339],"class_list":["post-221","post","type-post","status-publish","format-standard","hentry","category-commands","category-script","category-scripting","category-solaris","category-unix","tag-if-else","tag-if-else-if","tag-ksh-shell","tag-ksh-shell-script","tag-shell-script","tag-special-shell-variable"],"_links":{"self":[{"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/posts\/221","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/comments?post=221"}],"version-history":[{"count":1,"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/posts\/221\/revisions"}],"predecessor-version":[{"id":222,"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/posts\/221\/revisions\/222"}],"wp:attachment":[{"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/media?parent=221"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/categories?post=221"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.sysadmindayph.com\/blog\/wp-json\/wp\/v2\/tags?post=221"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nif then fi
\nif [[ $value -eq 7 ]];then
\n print \"$value is 7\"
\nfi<\/code>
\nor:<\/p>\nif [[ $value -eq 7 ]]
\nthen
\n print \"$value is 7\"
\nfi<\/code>or:<\/p>\nif [[ $value -eq 7 ]];then print \"$value is 7\";fi<\/p>\n
\nif [[ $name = \"John\" ]];then
\n print \"Your welcome, ${name}.\"
\nelse
\n print \"Good bye, ${name}!\"
\nfi<\/code><\/p>\nif then elif then else fi
\nif [[ $name = \"John\" ]];then
\n print \"Your welcome, ${name}.\"
\nelif [[ $name = \"Hanna\" ]];then
\n print \"Hello, ${name}, who are you?\"
\nelse
\n print \"Good bye, ${name}!\"
\nfi<\/code><\/p>\ncase esac
\ncase $var in
\n john|fred) print $invitation;;
\n martin) print $declination;;
\n *) print \"Wrong name...\";;
\nesac<\/code><\/p>\nwhile do done
\nwhile [[ $count -gt 0 ]];do
\n print \"\\$count is $count\"
\n (( count -= 1 ))
\ndone<\/code>
\nuntil do done
\nuntil [[ $answer = \"yes\" ]];do
\n print -n \"Please enter \\\"yes\\\": \"
\n read answer
\n print \"\"
\ndone<\/code>
\nfor var in list do done
\nfor foo in $(ls);do
\n if [[ -d $foo ]];then
\n print \"$foo is a directory\"
\n else
\n print \"$foo is not a directory\"
\n fi
\ndone<\/code>
\ncontinue…break
\nOne can skip the rest of a loop and directly go to the next iteration with: “continue”. <\/p>\nwhile read line
\ndo
\n if [[ $line = *.gz ]];then
\n continue
\n else
\n print $line
\n fi
\ndone<\/code>
\nOne can also prematurely leave a loop with: “break”. <\/p>\nwhile read line;do
\n if [[ $line = *!(.c) ]];then
\n break
\n else
\n print $line
\n fi
\ndone<\/code><\/p>\n#!\/bin\/ksh<\/p>\n
\ndo
\n grep -i $each \/etc\/passwd
\n if [[ $? -eq 1 ]]; then
\n echo \"$each does not exists.\"
\n sleep 2
\n continue;
\n else
\n echo \"$each exists\"
\n echo \"Deleting account.. \"
\n sleep 2
\n userdel $each
\n echo \"$each deleted\"
\n sleep 5
\n fi<\/p>\n