Line

wikipedia:line

Count lines:

• wc -l

Concatenate lines:

• cat file | tr '\n' ' '
• cat file | xargs
• ls | xargs

New line:

• echo

Merge every two lines:

• cat /path/tofile.txt | paste -d " " - -
• cat /path/tofile.txt | xargs -n2 -d'\n'

Add line:

• grep -qxF 'your text "additional text"' yourfile.txt || echo 'your text "additional text"' >> yourfile.txt

Remove first line:

• tail -n +2

Activities

• Concatenate lines

Related

• spit
• column
• uniq
• echo -n
• grep .
• Cisco IOS: line vty
• End of line
• Line, Instant Messaging

See also

• line, newline, characters, wc, column, Add line, Concatenate lines, Ansible: lineinfile, rpl, sed -i, fold (command)
• file, File system, directory, touch, mkdir, ls, ln truncate, fallocate, split, stat, inode, File descriptor, superblock, block size (blockdev), fuser, lsof, scrub, chattr, ulimit (nofiles), cp, mv, file (command), mkfifo, chmod

https://stackoverflow.com/a/9605450