{"id":183,"date":"2020-08-15T20:10:45","date_gmt":"2020-08-16T01:10:45","guid":{"rendered":"https:\/\/www.brezeale.com\/?p=183"},"modified":"2020-08-15T20:10:45","modified_gmt":"2020-08-16T01:10:45","slug":"bash-shell-examples","status":"publish","type":"post","link":"https:\/\/www.brezeale.com\/?p=183","title":{"rendered":"bash Shell Examples"},"content":{"rendered":"\n

I originally created this on June 23, 2004. These examples primarily use the for<\/code> loop in the bash shell.<\/p>\n\n\n\n

    \n
  1. Count the number of lines with the_word <\/span>in each .txt<\/span> file<\/li>\n
    \n \n \n
    \n 
    \nfor file in *.txt; do \n\tgrep the_word $file | wc -l\ndone\n<\/pre>        <\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  2. This code creates directories (under the current directory, as written) \n    for any groups whose names begin with dev-<\/span>.<\/li>\n  
     \n    \n       \n        
     \n          
    \nfor GRP in `getent group | cut -d: -f1 | grep ^dev-`; do\n\t\tmkdir $GRP\ndone\n<\/pre>        <\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  3. Create directories named dev1, dev2, …, dev10<\/span><\/li>\n  
     \n    \n       \n        
     \n          
    \nfor (( num=1; num <= 10; num++ )); do\n\t\tmkdir "dev$num"\ndone\n<\/pre>        <\/td>\n      <\/tr>\n    <\/table>\n    
    or<\/p>\n    \n      \n        
    \nfor num in $(seq 1 10); do\n\t\tmkdir dev$num\ndone   <\/pre>        <\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  4. If you need to have a special format, the Unix command seq<\/span> \n    supports some of the printf standards. For instance, to convert the image \n    files named frame001.jpg, frame002.jpg,…, frame999.jpg<\/span> \n  to GIFs, I can use<\/li>\n  
     \n    \n       \n        
     \n          
    \nfor num in $(seq -f %03g 1 999); do\n\t\tconvert frame$num.jpg frame$num.gif\ndone\n          <\/pre><\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  5. Change all files with the extension out<\/span> to lowercase<\/li>\n  
     \n    \n       \n        
     \n          
    \nfor file in *.out; do\n\tmv $file `echo $file | tr '[A-Z]' '[a-z]'`\ndone \n          <\/pre><\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  6. Change filenames with the extension chm<\/span> that consist of words separated by periods (e.g., this.is.a.long.name.chm<\/span>) to use underscores instead except for the period that typically exists between the prefix and file extension.  Here sed’s ‘-e’ option is used to combine expressions.<\/li>\n  
     \n    \n       \n        
     \n          
    \nfor file in *.chm; do \n\tmv $file `echo $file | sed -e 's\/\\.\/_\/g' -e 's\/_chm\/.chm\/'`\ndone\n<\/pre>        <\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  7. Find all directories which have files within 2 levels of the current location that have changed in the past day. Use sed to get just the directory name and tar it with the current date in the tar’ed filename. <\/li>\n  
     \n    \n       \n        
     \n          
    SRC=\"\/windows_data\/data\"\nDEST=\"\/windows_data\/data_backups\"\nDATE=`date '+%y%m%d'`\n\ncd $SRC\n\nfor file in `find . -maxdepth 2 -mtime -1 | sed 's\/\\.\\\/\/\/' | sed 's\/\\(.*\\)\\\/.*\/\\1\/' | sort|uniq`\ndo\n  if [ ! -e \"$file\" ]       # Check if file exists.\n  then\n    echo \"$file does not exist.\"; echo\n    continue                # On to next.\n  fi\n  if [ ! \"$file\" == \".\" ]\n  then\n    tar -czf $DEST\/$file$DATE.tgz $file \n  fi\ndone\n<\/pre>        <\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  8. Count the number of lines in each file with the extension dct<\/span> and divide it by 480.<\/li>\n  
     \n    \n       \n        
     \n          
    \nfor file in *.dct; do\n\tLC=`cat $file | wc -l`\n\techo $file\n\tCOUNT=$(echo \"scale=3; $LC \/ 480\" | bc)\n\techo \"  lines = \" $LC\", ratio = \" $COUNT\ndone\n          <\/pre><\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  9. For each line in test.txt<\/span>, count the number of words.<\/li>\n  
     \n    \n       \n        
     \n          
    \nwhile read line; do  \n\techo $line | wc -w; \ndone < test.txt\n          <\/pre><\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  10. extract the files for user1010 from the compressed files<\/li>\n  
     \n    \n       \n        
     \n          
    \nfor file in *sequence.csv.tgz; do \n\ttar tvzf $file | grep user1010 |sed 's\/.*\\(user1010.*\\)\/\\1\/' > tempvar\n\ttar xzf $file `cat tempvar`\ndone\n<\/pre><\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  11. combine the contents of all user files (which have names of the form user1234-sequence.csv<\/span>), with each user’s part preceded by the user name and separated by a blank line<\/li>\n  
     \n    \n       \n        
     \n          
    \nfor file in user*sequence.csv; do \n\tprefix=`basename $file -sequence.csv`\n\techo $prefix >> allusers.txt\n\tcat $file >> allusers.txt\n\techo \"\" >> allusers.txt\ndone\n<\/pre><\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n  
  12. rename files of the form test3-q01.c, test3-q02.c,…<\/span> to test2-q01.c, test2-q02.c,…<\/span><\/li>\n  
     \n    \n       \n        
     \n          
    \nfor file in test3*.c; do \n    suf=`echo $file | sed 's\/test3-\/\/'`\n    mv $file test2-$suf\ndone\n<\/pre><\/td>\n      <\/tr>\n    <\/table>\n  <\/blockquote>\n<\/ol>\n\n\n\n
    <\/p>\n","protected":false},"excerpt":{"rendered":"
    I originally created this on June 23, 2004. These examples primarily use the for loop in the bash shell. Count the number of lines with the_word in each .txt file for file in *.txt; do grep the_word $file | wc -l done This code creates directories (under the current directory, as written) for any groups whose names begin with dev-. for GRP in `getent group | cut -d: -f1 | grep ^dev-`; do mkdir $GRP done Create directories named dev1,…<\/p>\n
     Read More  Read More<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[7],"tags":[],"class_list":["post-183","post","type-post","status-publish","format-standard","hentry","category-linux"],"_links":{"self":[{"href":"https:\/\/www.brezeale.com\/index.php?rest_route=\/wp\/v2\/posts\/183","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.brezeale.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.brezeale.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.brezeale.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.brezeale.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=183"}],"version-history":[{"count":1,"href":"https:\/\/www.brezeale.com\/index.php?rest_route=\/wp\/v2\/posts\/183\/revisions"}],"predecessor-version":[{"id":184,"href":"https:\/\/www.brezeale.com\/index.php?rest_route=\/wp\/v2\/posts\/183\/revisions\/184"}],"wp:attachment":[{"href":"https:\/\/www.brezeale.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=183"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.brezeale.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=183"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.brezeale.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=183"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}