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Random Talk on Random Thoughts

Find Files for Vim to Edit in Bash

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Background

Since copying and pasting the output of a command can be a tedious job. For example, if you want to create your blog using a framework, you may first logon to your GitHub account and create an empty repository there, then git clone Octopress/Jekyll-Bootstrap from GitHub, reset the origin URL, and input the new URL based on the old one.

After having created a repository online, you will see the URL of the repository using the SSH protocol. If one doesn’t want to repeat the start of the URL git@github.com:, one may use the bash commands introduced in the previous post to extract its useful parts for the sed substitution.

$ git remote -v
octopress	git@github.com:imathis/octopress.git (fetch)
octopress	git@github.com:imathis/octopress.git (push)
origin	git@github.com:VincentTam/vincenttam.github.io.git (fetch)
origin	git@github.com:VincentTam/vincenttam.github.io.git (push)
$ name=userName; repo=repoName
$ git remote -v | sed -n '3{p;q}' | awk '{print $2}' | sed -r \
"s;(\w*)/(.*).git;$name/$repo.git;"
$ unset name repo

Problem

I tried extracting a list of Markdown files containing a particular word and passing them to Vim as arguments using find, grep and xargs. Unluckily, I got an error.

$ find source/_posts/ -name "*.markdown" -exec grep -q ^tag {} \; \
> -print | xargs vi
Vim: Warning: Input is not from a terminal
3 files to edit
$

Note: Without the -print flag, the above command won’t work.

Solution

As a result, I searched “vim warning input is not from a terminal xargs” on Google, and found this question very useful. I should have wrapped the find command like $(find ...).

$ vi $(find source/_posts/ -name "*.markdown" -exec \
> grep -q ^tag {} \; -print | xargs)
3 files to edit

Facts learnt

sed

  • 3{p;q}: quit after printing the third line for the sake of efficiency
  • -r: use extended regular expression to save the trouble of escaping () for submatches.
  • -n: suppress standard output.
  • Enclose the expression
    • with single quotes to disable interpretation of bash variables
    • with double quotes to enable interpretation of bash variables.
  • One can replace the delimiter / in the expression s/{pat}/{repl}/ by any one character from _;#| .
  • Specify a custom delimiter like \%.%s%foo%bar%. (The variable/range . is needed.)

bash

  • Set variables using var1=value1;var2=value2;...
  • Unset variable usign unset var1 var2 ...

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