Differences

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--- sed_notes [2021/01/28 20:16] – [backup with timestamp] raju
+++ sed_notes [2021/01/28 21:50] (current) – raju
@@ Line 1: / Line 1: @@
 ==== replace text between two lines with a file ====
+tags | line numbers, sed command to insert a file
 Replace lines between \$start and \$end in main.txt with contents of part.txt
@@ Line 52: / Line 53: @@
 j k l
 </code>
+==== insert file at the beginning of another file ====
+This will insert part.txt at the beginning of main.txt.
+<code>
+sed -e "1 e cat part.txt" main.txt
+</code>
+Example:
+<code>
+$ cat main.txt
+a b c
+d e f
+g h i
+j k l
+$ cat part.txt
+x y z
+p q r
+s t u
+$ sed -e "1 e cat part.txt" main.txt
+x y z
+p q r
+s t u
+a b c
+d e f
+g h i
+j k l
+</code>
+Found it in: https://unix.stackexchange.com/questions/337435/sed-insert-file-at-top-of-another
 ==== backup with timestamp ====
-tags | sed create backup
+tags | sed create backup, YYYYMMDD_HHMMSS
 <code>
-sed "-i_asof_`date +%Y%m%d_%M%S`" -e 's/foo/bar/g' main.txt
+sed "-i_asof_`date +%Y%m%d_%H%M%S`" -e 's/foo/bar/g' main.txt
 </code>
-will backup to something like main.txt_asof_20210128_2231
+will backup to something like main.txt_asof_20210128_151656
 <code>
@@ Line 65: / Line 98: @@
 </code>
 will backup to something like main.txt.2021-01-28
+==== sed do not change line endings ====
+<code>
+sed -b
+</code>
+Ref:- https://stackoverflow.com/questions/4652652/preserve-line-endings
 ==== replace double quote with single quote ====
   sed "s/\"/'/g"