Replace  ΒΆ

  • Text replacement:

    $ sed 's/string to replace/replacement string/g' original-file.txt > new-file.txt
    
  • Dynamic, in-place replacement of unreleased text with today’s date:

    $ sed -i "s/unreleased/`date +'%Y-%m-%d'`/" ./changelog.md
    
  • Update the release date in citation.cff file:

    $ perl -pi -e "s/date-released: \d+-\d+-\d+/date-released: $(date +'%Y-%m-%d')/" ./citation.cff
    
  • Replace all occurrences of str1 by str2 in all files below the /folder path:

    $ find /folder -type f -print -exec sed -i 's/str1/str2/g' "{}" \;
    
  • Same as above but ignore all content of .svn folders and .zip files:

    $ find /folder -type f -not -regex ".*\/\.svn\/.*" -not -iname "*\.zip" -print -exec sed -i 's/str1/str2/g' "{}" \;
    
  • Remove trailing spaces and tabs in every XML files:

    $ find /folder -iname "*.xml" -exec sed -i 's/[ \t]*$//' "{}" \;
    
  • Place a new --- line at the start of each .markdown files ( see result  ):

    $ find ./folder -iname "*.markdown" -exec sed -i '1s/^/---\n/' "{}" \;
    
  • Place a new --- line before the first empty line of each .markdown files ( see result  ):

    $ find ./folder -iname "*.markdown" -exec sed -i '0,/^$/s//---\n/' "{}" \;
    
  • Remove lines starting with prefix1: or prefix2: in all .markdown files:

    $ find /folder -iname "*.markdown" -exec perl -p -i -e 's/(prefix1|prefix2): .*\n//sg' "{}" \;
    
  • Strip time from date: prefixed lines and quote the value. I.e. replace all occurrences of date: 2012-01-01 00:00:00 +0000 by date: "2012-01-01" :

    $ find /folder -iname "*.markdown" -exec perl -p -i -e 's/date: (\d+-\d+-\d+) .*\n/date: "$1"\n/sg' "{}" \;
    
  • Remove lines matching a regex (encoding particular markdown TOC entries ), save the result in place and save a backup of the original content in a .bak file:

    $ gawk -i inplace -v INPLACE_SUFFIX=.bak '!/^- \[(Contribute|Contributing|Licence|License)\]\(#.+\)$/{print}' ./readme.md
    
  • Use sed address ranges to spot, in a Markdown file, all blocks led by a ::: directive, and terminated by a blank line. Then replace in each of these matched blocks the a letter by XXX . Notice how a occurrences outside the blocks are not replaced by XXX :

    $ cat ./example.md
    
    This is a code block:
    
    :::shell-session
    β†’ apache
    β†’ java
    β†’ python
    
    This is another block:
    
    :::shell-session
    β†’ rust
    β†’ haskell
    β†’ javascript
    
    This is a random sentence.
    
    $ sed "/^:::/,/^$/ s/a/XXX/g" ./example.md
    
    This is a code block:
    
    :::shell-session
    β†’ XXXpXXXche
    β†’ jXXXvXXX
    β†’ python
    
    This is another block:
    
    :::shell-session
    β†’ rust
    β†’ hXXXskell
    β†’ jXXXvXXXscript
    
    This is a random sentence.
    
  • In the same spirit as above but this time to spot indented blocks starting with ::: , then wrap them into triple-backticks fences:

    $ cat ./example.md
    
    This is a code block:
    
        :::shell-session
        β†’ apache
        β†’ java
        β†’ python
    
    This is another block:
    
        :::shell-session
        β†’ rust
        β†’ haskell
        β†’ javascript
    
    This is a random sentence.
    
    $ find ./folder -iname "*.md" \
    > -exec sed -i "/^    :::/,/^$/ s/^$/    \`\`\`\n/" "{}" \; \
    > -exec sed -i "/^    :::/,/^$/ s/:::/\`\`\`/"      "{}" \;
    
    $ cat ./example.md
    
    This is a code block:
    
        ```shell-session
        β†’ apache
        β†’ java
        β†’ python
        ```
    
    This is another block:
    
        ```shell-session
        β†’ rust
        β†’ haskell
        β†’ javascript
        ```
    
    This is a random sentence.
    
  • Strip in-place the block of text starting with XXX and ending with an empty line:

    $ cat ./example.md
    
    This is a code block:
    
    XXX{shell-session}
    β†’ apache
    β†’ java
    β†’ python
    
    This is a random sentence.
    
    $ perl -i -ne "print if not /XXX/ .. /^$/" ./example.md
    
    $ cat ./example.md
    
    This is a code block:
    
    This is a random sentence.
    
  • Same as above, but with sed :

    $ sed -i "/^XXX/,/^$/ d" ./example.md
    
  • Python one-liner to delete the first occurrence of a block of text delimited by triple-backticks fences. Contrary to methods above, this one is not distracted by blank lines within the text block:

    $ python -c 'import re; from pathlib import Path; file = Path("./example.md"); file.write_text(re.sub(r"^\`\`\`.*?\`\`\`\n\n", "", file.read_text(), count=1, flags=re.MULTILINE | re.DOTALL))'
    
  • Append the content of the addendum.txt file to all .markdown files:

    $ find ./folder -iname "*.markdown" -print -exec bash -c 'cat ./addendum.txt >> "{}"' \;
    
  • Replace all accentuated characters by their non-accentuated variants (thanks Matthieu for the tip):

    $ echo "éÈça-$" | iconv -t ASCII//translit
    

Date & Time  ΒΆ

  • Get the date of last week:

    $ date +"%Y-%m-%d" -d last-week
    
  • Get the current date in english:

    $ env LC_TIME=en date +"%a %b %d %Y"
    
  • Get the number of seconds since epoch  :

    $ date +%s
    
  • Convert back epoch time to human-readable date:

    $ date --date=@1234567890
    

Transcoding  ΒΆ

  • In place charset transcoding:

    $ recode utf-8..latin-1 utf8text.txt
    

Edition  ΒΆ

Additional References  ΒΆ