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linux:bashshell [2016/01/15 04:43] – [variable local and global] adminlinux:bashshell [2022/10/29 16:15] (current) – external edit 127.0.0.1
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 Bash script: http://www.linuxconfig.org/Bash_scripting_Tutorial Bash script: http://www.linuxconfig.org/Bash_scripting_Tutorial
 ====== Linux Bash Shell Script ====== ====== Linux Bash Shell Script ======
-===== create simple code =====+===== Simple code =====
   * create helloworld.sh<code bash>   * create helloworld.sh<code bash>
 cat > helloworld.sh cat > helloworld.sh
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 ==== Bitwise operators ==== ==== Bitwise operators ====
 ==== comparision operators ==== ==== comparision operators ====
-=== integer comparison ===+=== Integer comparison ===
 -eq : is equal to<code bash> -eq : is equal to<code bash>
 if [ "$a" -eq "$b" ] if [ "$a" -eq "$b" ]
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 (("$a" >= "$b")) (("$a" >= "$b"))
 </code> </code>
-=== string comparison ===+=== String comparison ===
 String Comparisions: String Comparisions:
   * =: is equal to<code bash>   * =: is equal to<code bash>
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 echo $date echo $date
 </code> </code>
-==== loop with while ====+==== Loop with while ====
 loop with while:<code bash> loop with while:<code bash>
 <code bash> <code bash>
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 done < /tmp/a1.txt done < /tmp/a1.txt
 </code> </code>
-==== array ====+==== Array ====
   * Init the array and access the elements of array:<code bash>   * Init the array and access the elements of array:<code bash>
 arr=( zero one two three four five ) arr=( zero one two three four five )
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 </code> </code>
 ==== Find files that contain the text ==== ==== Find files that contain the text ====
 +  * Simple<code bash>
 +grep -rnw . -e "Begin Facebook Code"
 +</code>
 +  * Custom find with regular expression<code bash>
 +grep -rnw . -e 'mongo.*'
 +</code>
 +==== Find files that file name length > 29 ====
 +<code bash>
 +for i in `ls -1`;do sub_i=(`echo $i|cut -d'-' -f 1`);lensub_i=${#sub_i}; if [ $lensub_i -ge 29 ]; then echo $sub_i;echo $i; fi  done
 +</code>
 +==== Manipulating String ====
 +refer: http://tldp.org/LDP/abs/html/string-manipulation.html
 +  * String length: **${#string}**:<code bash>
 +str="First String"; echo ${#str}
 +</code>output:<code>
 +12
 +</code>
 +  * Replace String:<code>${string//substring/replacement}</code>Example:<code bash>
 +str="First String"; echo ${str//First/Second}
 +</code>output:<code>
 +Second String
 +</code>
 +==== update array to file ====
 +Below is array configs.txt:<code>
 +c1 = 0,4,5,8,9,12,13,16,17,19,22,21,45,2,3,6,7,10,11,14,15,20,1,23,44,50,26,27,28,29,30,31,32,33,34,35,38,49,47,18,36,37,24,39,40,41,42,43,46,48,25,51
 +c2 = 51,4,5,8,9,12,13,16,17,25,22,21,45,2,3,6,7,10,11,14,15,20,1,23,44,50,26,27,28,29,30,31,32,33,34,35,38,49,47,18,36,37,24,39,40,0,42,43,46,48,19,41
 +c3 = 26,27,33,34,8,9,12,13,40,41,0,30,31,2,3,6,7,10,11,14,15,20,21,23,44,50,45,1,28,29,32,19,22,4,5,35,38,49,47,18,36,37,24,39,16,17,42,43,46,48,25,51
 +</code>
 +update array to files:
 <code bash> <code bash>
-grep -rnw babyshopvn -e "Begin Facebook Code"+index=0;for i in `cat configs.txt | awk '{print $3}'`; do let "index = $index + 1";echo $i > c$index.txt; done
 </code> </code>
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