{"id":3236,"date":"2014-06-23T21:16:33","date_gmt":"2014-06-23T13:16:33","guid":{"rendered":"http:\/\/rmohan.com\/?p=3236"},"modified":"2014-06-23T21:51:23","modified_gmt":"2014-06-23T13:51:23","slug":"exit-status-code","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=3236","title":{"rendered":"exit status code"},"content":{"rendered":"

How to check the exit status code<\/a><\/h3>\n
<\/div>\n
\n

When a command finishes execution, it returns an exit code. The exit code is not displayed on the screen by default. To examine the exit code, you need to examine a special variable, “$?<\/span>”<\/p>\n

Say, you are searching for a string in a text file.<\/p>\n

$ grep x1y2z3 somefile.txt\r\n$<\/pre>\n
The standard output of the command returns null, which is a pretty good indication that the string cannot be found in the file.<\/p>\n
But what if you embed the grep command in a script? How can you tell if the string is found or not?<\/p>\n
Checking the exit code will tell you. Let’s first try it out interactively.<\/p>\n
$ grep x1y2z3 somefile.txt\r\n$ echo $?\r\n1<\/pre>\n
Note that in bash, the exit status is 0 if the command succeeded, and 1 if failed. For\u00a0<\/span>grep,<\/span>\u00a0<\/span>0 means that the string was found, and 1 (or higher), otherwise.<\/p>\n
To check the exit status in a script, you may use the following pattern:<\/p>\n
somecommand  argument1 argument2\r\nRETVAL=$?\r\n[ $RETVAL -eq 0 ] && echo Success\r\n[ $RETVAL -ne 0 ] && echo Failure<\/pre>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
How to check the exit status code <\/p>\n
When a command finishes execution, it returns an exit code. The exit code is not displayed on the screen by default. To examine the exit code, you need to examine a special variable, “$?”<\/p>\n
Say, you are searching for a string in a text file.<\/p>\n
 $ grep x1y2z3 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3236"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3236"}],"version-history":[{"count":2,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3236\/revisions"}],"predecessor-version":[{"id":3238,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3236\/revisions\/3238"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3236"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3236"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3236"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}