[student@studentvm1 testdir]$ File="TestFile1" ; touch $File ; if [ -s $File ] ; then echo "$File exists and contains data." ; else echo "$File does not exist or is empty." ; fi TestFile1 does not exist or is empty. 向文件添加一些内容,然后再测试一次: [student@studentvm1 ...
GREP_COLOR is still supported, but its setting does not have priority. WHEN is never, always, or auto.-A NUM, --after-context=NUM Print NUM lines of trailing context after matching lines. Places a line containing a group separator (--) between contiguousgroupsof matches.-B NUM, --before...
、 作为bash脚本的一部分,我正在尝试构建一个过滤器,当传递不正确的文件名时,该过滤器将退出脚本: echo "'$1' is not a valid name"fi 在调试器中测试RegEx时,它匹配正确的字符串,例如:DCS-9 浏览11提问于2019-11-08得票数 1 回答已采纳 3回答 在if语句中使用grep 、、、 我的目标是编写一...
以下是两个变量: A=$(cat ${FICHIER_BROKERS} | grep ${DATABASE_NAME} | grep dbo.${TABLE_NAME}\ | awk '{print $4}') B=$(cat ${FICHIER_SUBSCRIBERS} | grep ${DATABASE_NAME} | grep dbo_${TABLE_NAME}_CT | awk '{print $4" "$5}' | sed "s/...$//" | s 浏览1提问于20...
This line contains some error. This is the previous line. This is the line we are searching for. 上述示例中,grep -B 2 "error" file.txt返回了匹配行之前的两行内容。 返回匹配行之后的内容 $ grep -A 2 "warning" file.txt This is the line we are searching for. ...
[1] If a given commandisa builtin, a message such as is a shell builtinprints. To test this conditionprogrammatically, use something liketype 2>/dev/null | grep -q builtin && echo "IS A BUILTIN" (All major POSIX-compatible shells (bash,zsh,dash,ksh), even though the wording of...
will not match the string The if construct can be echo $newstring| grep -oP "^[^'\!'@#\$%^\&*()_+]*['\!'@#\$%^\&*()_+][^'\!'@#\$%^\&*()_+]+$" if [[ $? -eq 0 ]] > /dev/null then echo Error - Does not contain One Special Character - $newstr...
All the code snippets are written in the MyScript.sh file, while the dummy.txt file contains some sample data we used in our scripts. Using -q Option with grep Use the -q option with grep to check if the grep command result is empty. Use -q Option with grep in MyScript.sh 1 2...
# 其中-q用来阻止echo的输出grep获得的内容 then echo"$1 contains at last on occurence of root"elseecho"$1 does not contain"fi exit0并chmod777test.sh, 执行: ./test.h /etc/passwd 之后,返回 File contains at last on occurence of root4.一个if/then结构可以包含多级比较和tests(嵌套)if[ condi...
grep -e replaces egrep as the preferred way to search for many patterns at once. The following example uses a contacts list (contacts.txt) with a fixed structure, such that each contact has four lines associated with it and each line contains one field. Apart from that, nothing else is ...